diff --git a/src/main.rs b/src/main.rs
index 368500e..45e1320 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,12 +1,13 @@
 use chrono::DateTime;
 use clap::Parser as _;
-use std::{collections::BTreeSet, io::Write as _, time::Duration};
+use std::time::Duration;
 
 use prelude::*;
 
 #[cfg(test)]
 mod tests;
 
+mod output;
 mod prelude;
 mod wac_campfire;
 mod wac_common_ninja;
@@ -30,31 +31,12 @@ struct CalendarUi {
     short_name: String,
 }
 
-#[derive(Deserialize)]
-struct ConfigOutput {
-    /// Used as the OpenGraph description in meta tags
-    description: String,
-
-    hide_summaries: BTreeSet<String>,
-
-    /// Hide all these UIDs from the final output
-    hide_uids: BTreeSet<String>,
-
-    /// Timezone to use for output (e.g. "Antarctica/South_Pole")
-    ///
-    /// <https://en.wikipedia.org/wiki/List_of_tz_database_time_zones>
-    timezone: chrono_tz::Tz,
-
-    /// Used as the page title and OpenGraph title in meta tags
-    title: String,
-}
-
 #[derive(Deserialize)]
 struct Config {
     campfires: Vec<wac_campfire::Config>,
     common_ninjas: Vec<wac_common_ninja::Config>,
     icals: Vec<wac_ical::Config>,
-    output: ConfigOutput,
+    output: output::Config,
 }
 
 impl Config {
@@ -69,6 +51,26 @@ impl Config {
             )
             .chain(self.icals.iter().map(|ical| ical.dl.clone()))
     }
+
+    fn upstreams(&self) -> Vec<CalendarUi> {
+        let Self {
+            campfires,
+            common_ninjas,
+            icals,
+            output: _,
+        } = self;
+
+        let mut upstreams: Vec<_> = campfires
+            .iter()
+            .map(|cfg| &cfg.ui)
+            .cloned()
+            .chain(common_ninjas.iter().map(|cfg| &cfg.ui).cloned())
+            .chain(icals.iter().map(|cfg| &cfg.ui).cloned())
+            .collect();
+        upstreams.sort_by_key(|ui| ui.short_name.clone());
+
+        upstreams
+    }
 }
 
 #[derive(clap::Parser)]
@@ -152,22 +154,6 @@ struct EventInstance {
     url: Option<String>,
 }
 
-impl EventInstance {
-    fn filter(&self, config_output: &ConfigOutput) -> bool {
-        if let Some(uid) = &self.uid
-            && config_output.hide_uids.contains(uid)
-        {
-            return false;
-        }
-        if let Some(summary) = &self.summary
-            && config_output.hide_summaries.contains(summary)
-        {
-            return false;
-        }
-        true
-    }
-}
-
 #[derive(Default)]
 struct Data {
     campfires: Vec<wac_campfire::Calendar>,
@@ -197,7 +183,7 @@ fn read_data_from_disk(config: &Config) -> Result<Data> {
 
 fn process_data<'a>(
     data: &'a Data,
-    config_output: &'a ConfigOutput,
+    config_output: &'a output::Config,
     now: DateTime<chrono_tz::Tz>,
 ) -> Result<Vec<EventInstance>> {
     let params = Parameters::new(now)?;
@@ -208,7 +194,7 @@ fn process_data<'a>(
         for ev in campfire
             .event_instances(&params)?
             .into_iter()
-            .filter(|x| x.filter(config_output))
+            .filter(|x| config_output.filter(x))
         {
             instances.push(ev);
         }
@@ -218,7 +204,7 @@ fn process_data<'a>(
         for ev in common_ninja
             .event_instances(&params)?
             .into_iter()
-            .filter(|x| x.filter(config_output))
+            .filter(|x| config_output.filter(x))
         {
             instances.push(ev);
         }
@@ -228,7 +214,7 @@ fn process_data<'a>(
         for ev in ical
             .event_instances(&params)?
             .into_iter()
-            .filter(|x| x.filter(config_output))
+            .filter(|x| config_output.filter(x))
         {
             instances.push(ev);
         }
@@ -238,187 +224,6 @@ fn process_data<'a>(
     Ok(instances)
 }
 
-fn output_html(
-    config: &ConfigOutput,
-    instances: &[EventInstance],
-    now: DateTime<chrono_tz::Tz>,
-) -> Result<()> {
-    let today = now.date_naive();
-    let mut last_month_printed: Option<String> = None;
-    let mut last_date_printed = None;
-    let mut html_list = vec![];
-    let mut day_list = vec![];
-    for ei in instances {
-        let date = ei.dtstart.date_naive();
-        let past = date < today;
-        let month = date.format("%B").to_string();
-        match last_month_printed {
-            Some(ref x) if *x == month => {}
-            None | Some(_) => {
-                // FIXME: De-dupe
-                if !day_list.is_empty() {
-                    html_list.push(maud::html! {
-                        ul { @for entry in day_list {
-                            (entry)
-                        } }
-                    });
-                    day_list = vec![];
-                }
-
-                html_list.push(maud::html! {
-                    h2 { (month) }
-                });
-                last_month_printed = Some(month);
-            }
-        }
-        if last_date_printed != Some(date) {
-            // FIXME: De-dupe
-            if !day_list.is_empty() {
-                html_list.push(maud::html! {
-                    ul { @for entry in day_list {
-                        (entry)
-                    } }
-                });
-                day_list = vec![];
-            }
-            if past {
-                html_list.push(maud::html! {
-                    p class="past"{ s { (date.format("%-d %A")) } }
-                });
-            } else {
-                let date_s = date.format("%-d %A");
-                let id = date.format("%F");
-                html_list.push(maud::html! {
-                    h3 id=(id) { (date_s) " " a href=(format!("#{id}")) title=(format!("Permalink to {date_s}")) {"🔗"} }
-                    hr{}
-                });
-            }
-
-            last_date_printed = Some(date);
-        }
-        let time = ei.dtstart.time();
-        let time = time
-            .map(|t| t.format("%l:%M %P").to_string())
-            .unwrap_or_else(|| "No time listed".to_string());
-
-        let summary = ei
-            .summary
-            .as_deref()
-            .unwrap_or("Data error BXH45NAR - No summary in event");
-        let summary = if let Some(url) = &ei.url {
-            maud::html! {a href=(url) {(summary)}}
-        } else {
-            maud::html! {(summary)}
-        };
-
-        if past {
-            day_list.push(maud::html! {
-                li class="past" { (time) " - " (summary) }
-            });
-        } else {
-            let calendar_link = if let Some(html_url) = &ei.calendar_ui.html_url {
-                maud::html! { a href=(html_url) { (ei.calendar_ui.short_name) } }
-            } else {
-                maud::html! { (ei.calendar_ui.short_name)}
-            };
-
-            // This is where the main stuff happens
-
-            tracing::debug!(uid = ei.uid, summary = ei.summary);
-            day_list.push(maud::html! {
-                li { details {
-                    summary { (time) " - " (summary) }
-                    ul {
-                        li { (calendar_link) " calendar" }
-                        @if let Some(location) = &ei.location {
-                            li { "Location: " (location) }
-                        }
-                    }
-                }
-            } });
-        }
-    }
-    // FIXME: De-dupe
-    if !day_list.is_empty() {
-        html_list.push(maud::html! {
-            ul { @for entry in day_list {
-                (entry)
-            } }
-        });
-    }
-
-    std::fs::create_dir_all("output")?;
-    {
-        let temp_path = "output/calendars.html.tmp";
-        let final_path = "output/calendars.html";
-        let mut f = std::fs::File::create(temp_path)?;
-
-        f.write_all("".as_bytes())?;
-        std::fs::rename(temp_path, final_path)?;
-    }
-
-    {
-        let temp_path = "output/index.html.tmp";
-        let final_path = "output/index.html";
-        let mut f = std::fs::File::create(temp_path)?;
-        let css = r#"
-        <style>
-            body { 
-                font-family: sans-serif;
-                font-size: 14pt;
-                line-height: 1.6;
-                max-width: 700px; 
-            }
-            img {
-                max-width: 100%;
-                height: auto;
-            }
-            .past {
-                color: #888;
-            }
-        </style>
-        "#;
-
-        let description = &config.description;
-        let title = &config.title;
-
-        let s = maud::html! {
-            (maud::PreEscaped("<!DOCTYPE html>"))
-            html lang="en" {
-                head {
-                    meta http-equiv="Content-Type" content="text/html; charset=utf-8" {}
-                    meta name="viewport" content="width=device-width, initial-scale=1" {}
-                    (maud::PreEscaped(css))
-
-                    meta property="og:locale" content="en" {}
-                    meta property="og:type" content="website" {}
-
-                    meta name="description" content=(description) {}
-                    meta property="description" content=(description) {}
-                    meta property="og:description" content=(description) {}
-
-                    title { (title) }
-                    met property="og:title" content=(title) {}
-                }
-                body {
-                    h1 { (title) }
-                    img src="hero.webp" width="700" height="233" {}
-                    p { "Written at: " (now.format("%F %T")) }
-                    @for entry in html_list {
-                        (entry)
-                    }
-                }
-            }
-        }
-        .into_string();
-
-        f.write_all(s.as_bytes())?;
-        std::fs::rename(temp_path, final_path)?;
-    }
-
-    Ok(())
-}
-
 static APP_USER_AGENT: &str = concat!(
     env!("CARGO_PKG_NAME"),
     "_Z7FSRRA7/",
@@ -453,7 +258,7 @@ async fn do_everything(cli: &CliAuto) -> Result<()> {
 
     let data = read_data_from_disk(&config)?;
     let instances = process_data(&data, &config.output, now)?;
-    output_html(&config.output, &instances, now)?;
+    output::write_html(&config.output, &config.upstreams(), &instances, now)?;
     Ok(())
 }
 
@@ -491,7 +296,8 @@ fn main_debug_output(cli: CliDebugOutput) -> Result<()> {
     let tz = &config.output.timezone;
     let now = Utc::now().with_timezone(tz);
     let instances = process_data(&data, &config.output, now).context("Failed to process data")?;
-    output_html(&config.output, &instances, now).context("Failed to output HTML")?;
+    output::write_html(&config.output, &config.upstreams(), &instances, now)
+        .context("Failed to output HTML")?;
 
     Ok(())
 }
diff --git a/src/output.rs b/src/output.rs
new file mode 100644
index 0000000..250cb08
--- /dev/null
+++ b/src/output.rs
@@ -0,0 +1,269 @@
+//! The code that writes HTML for web browsers to read
+
+use chrono::DateTime;
+use std::{collections::BTreeSet, io::Write as _};
+
+use crate::{EventInstance, prelude::*};
+
+const CSS: &str = r#"
+<style>
+    body { 
+        font-family: sans-serif;
+        font-size: 14pt;
+        line-height: 1.6;
+        max-width: 700px; 
+    }
+    img {
+        max-width: 100%;
+        height: auto;
+    }
+    .past {
+        color: #888;
+    }
+</style>
+"#;
+
+#[derive(Deserialize)]
+pub(crate) struct Config {
+    /// Used as the OpenGraph description in meta tags
+    description: String,
+
+    hide_summaries: BTreeSet<String>,
+
+    /// Hide all these UIDs from the final output
+    hide_uids: BTreeSet<String>,
+
+    /// Timezone to use for output (e.g. "Antarctica/South_Pole")
+    ///
+    /// <https://en.wikipedia.org/wiki/List_of_tz_database_time_zones>
+    pub(crate) timezone: chrono_tz::Tz,
+
+    /// Used as the page title and OpenGraph title in meta tags
+    title: String,
+}
+
+impl Config {
+    pub(crate) fn filter(&self, instance: &EventInstance) -> bool {
+        if let Some(uid) = &instance.uid
+            && self.hide_uids.contains(uid)
+        {
+            return false;
+        }
+        if let Some(summary) = &instance.summary
+            && self.hide_summaries.contains(summary)
+        {
+            return false;
+        }
+        true
+    }
+}
+
+fn calendar_link(calendar_ui: &crate::CalendarUi) -> maud::PreEscaped<String> {
+    if let Some(html_url) = &calendar_ui.html_url {
+        maud::html! { a href=(html_url) { (calendar_ui.short_name) } }
+    } else {
+        maud::html! { (calendar_ui.short_name)}
+    }
+}
+
+pub(crate) fn write_html(
+    config: &Config,
+    upstreams: &[crate::CalendarUi],
+    instances: &[EventInstance],
+    now: DateTime<chrono_tz::Tz>,
+) -> Result<()> {
+    let today = now.date_naive();
+    let mut last_month_printed: Option<String> = None;
+    let mut last_date_printed = None;
+    let mut html_list = vec![];
+    let mut day_list = vec![];
+    for ei in instances {
+        let date = ei.dtstart.date_naive();
+        let past = date < today;
+        let month = date.format("%B").to_string();
+        match last_month_printed {
+            Some(ref x) if *x == month => {}
+            None | Some(_) => {
+                // FIXME: De-dupe
+                if !day_list.is_empty() {
+                    html_list.push(maud::html! {
+                        ul { @for entry in day_list {
+                            (entry)
+                        } }
+                    });
+                    day_list = vec![];
+                }
+
+                html_list.push(maud::html! {
+                    h2 { (month) }
+                });
+                last_month_printed = Some(month);
+            }
+        }
+        if last_date_printed != Some(date) {
+            // FIXME: De-dupe
+            if !day_list.is_empty() {
+                html_list.push(maud::html! {
+                    ul { @for entry in day_list {
+                        (entry)
+                    } }
+                });
+                day_list = vec![];
+            }
+            if past {
+                html_list.push(maud::html! {
+                    p class="past"{ s { (date.format("%-d %A")) } }
+                });
+            } else {
+                let date_s = date.format("%-d %A");
+                let id = date.format("%F");
+                html_list.push(maud::html! {
+                    h3 id=(id) { (date_s) " " a href=(format!("#{id}")) title=(format!("Permalink to {date_s}")) {"🔗"} }
+                    hr{}
+                });
+            }
+
+            last_date_printed = Some(date);
+        }
+        let time = ei.dtstart.time();
+        let time = time
+            .map(|t| t.format("%l:%M %P").to_string())
+            .unwrap_or_else(|| "No time listed".to_string());
+
+        let summary = ei
+            .summary
+            .as_deref()
+            .unwrap_or("Data error BXH45NAR - No summary in event");
+        let summary = if let Some(url) = &ei.url {
+            maud::html! {a href=(url) {(summary)}}
+        } else {
+            maud::html! {(summary)}
+        };
+
+        if past {
+            day_list.push(maud::html! {
+                li class="past" { (time) " - " (summary) }
+            });
+        } else {
+            // This is where the main stuff happens
+
+            tracing::debug!(uid = ei.uid, summary = ei.summary);
+            day_list.push(maud::html! {
+                li { details {
+                    summary { (time) " - " (summary) }
+                    ul {
+                        li { (calendar_link(&ei.calendar_ui)) " calendar" }
+                        @if let Some(location) = &ei.location {
+                            li { "Location: " (location) }
+                        }
+                    }
+                }
+            } });
+        }
+    }
+    // FIXME: De-dupe
+    if !day_list.is_empty() {
+        html_list.push(maud::html! {
+            ul { @for entry in day_list {
+                (entry)
+            } }
+        });
+    }
+
+    std::fs::create_dir_all("output")?;
+    {
+        let temp_path = "output/calendars.html.tmp";
+        let final_path = "output/calendars.html";
+        let mut f = std::fs::File::create(temp_path)?;
+
+        let description = "A list of upstream calendars used by this Wide-Angle Calendar instance";
+        let title = "Upstream calendars";
+
+        let s = maud::html! {
+            (maud::PreEscaped("<!DOCTYPE html>"))
+            html lang="en" {
+                head {
+                    meta http-equiv="Content-Type" content="text/html; charset=utf-8" {}
+                    meta name="viewport" content="width=device-width, initial-scale=1" {}
+                    (maud::PreEscaped(CSS))
+
+                    meta property="og:locale" content="en" {}
+                    meta property="og:type" content="website" {}
+
+                    meta name="description" content=(description) {}
+                    meta property="description" content=(description) {}
+                    meta property="og:description" content=(description) {}
+
+                    title { (title) }
+                    met property="og:title" content=(title) {}
+                }
+                body {
+                    h1 { (title) }
+                    p {
+                        a href="index.html" { "Wide-Angle Calendar" }
+                        " / "
+                        a href="calendars.html" { (title) }
+                    }
+
+                    p { "Written at: " (now.format("%F %T")) }
+                    p { "These are the calendars that Wide-Angle Calendar pulls from." }
+
+                    ol {
+                        @for upstream in upstreams {
+                            li { (calendar_link(upstream)) }
+                        }
+                    }
+                }
+            }
+        }
+        .into_string();
+
+        f.write_all(s.as_bytes())?;
+        std::fs::rename(temp_path, final_path)?;
+    }
+
+    {
+        let temp_path = "output/index.html.tmp";
+        let final_path = "output/index.html";
+        let mut f = std::fs::File::create(temp_path)?;
+
+        let description = &config.description;
+        let title = &config.title;
+
+        let s = maud::html! {
+            (maud::PreEscaped("<!DOCTYPE html>"))
+            html lang="en" {
+                head {
+                    meta http-equiv="Content-Type" content="text/html; charset=utf-8" {}
+                    meta name="viewport" content="width=device-width, initial-scale=1" {}
+                    (maud::PreEscaped(CSS))
+
+                    meta property="og:locale" content="en" {}
+                    meta property="og:type" content="website" {}
+
+                    meta name="description" content=(description) {}
+                    meta property="description" content=(description) {}
+                    meta property="og:description" content=(description) {}
+
+                    title { (title) }
+                    met property="og:title" content=(title) {}
+                }
+                body {
+                    h1 { (title) }
+                    img src="hero.webp" width="700" height="233" {}
+                    p { "Written at: " (now.format("%F %T")) }
+                    p { a href = "calendars.html" { "Upstream calendars" } }
+                    @for entry in html_list {
+                        (entry)
+                    }
+                }
+            }
+        }
+        .into_string();
+
+        f.write_all(s.as_bytes())?;
+        std::fs::rename(temp_path, final_path)?;
+    }
+
+    Ok(())
+}
diff --git a/src/wac_campfire.rs b/src/wac_campfire.rs
index 49e26ae..8520b21 100644
--- a/src/wac_campfire.rs
+++ b/src/wac_campfire.rs
@@ -19,11 +19,12 @@ pub(crate) struct Config {
 
 #[derive(Deserialize)]
 struct Event {
-    description: String,
+    #[serde(alias = "description")]
+    _description: String,
     #[serde(alias = "endDate")]
-    end_date: Option<String>,
+    _end_date: Option<String>,
     #[serde(alias = "endTime")]
-    end_time: Option<String>,
+    _end_time: Option<String>,
     #[serde(alias = "eventName")]
     event_name: String,
     location: String,
diff --git a/src/wac_common_ninja.rs b/src/wac_common_ninja.rs
index 05380d2..6a1d085 100644
--- a/src/wac_common_ninja.rs
+++ b/src/wac_common_ninja.rs
@@ -36,10 +36,11 @@ impl Config {
 #[derive(Deserialize)]
 struct Event {
     #[serde(alias = "durationInMinutes")]
-    duration_in_minutes: u32,
+    _duration_in_minutes: u32,
     timestamp: i64,
     title: String,
-    description: String,
+    #[serde(alias = "description")]
+    _description: String,
 }
 
 #[derive(Deserialize)]