diff --git a/rust/lon/src/cli.rs b/rust/lon/src/cli.rs
index b1efe1d..8cd9228 100644
--- a/rust/lon/src/cli.rs
+++ b/rust/lon/src/cli.rs
@@ -61,6 +61,8 @@ enum Commands {
     Freeze(SourceArgs),
     /// Unfreeze an existing source
     Unfreeze(SourceArgs),
+    /// Show the list of sources or a specific source
+    Show { name: Option<String> },
 
     /// Bot that opens PRs for updates
     Bot {
@@ -243,6 +245,7 @@ impl Commands {
             Self::Remove(args) => remove(directory, &args),
             Self::Freeze(args) => freeze(directory, &args),
             Self::Unfreeze(args) => unfreeze(directory, &args),
+            Self::Show { name } => show(directory, name),
 
             Self::Bot { commands } => match commands {
                 BotCommands::GitLab => bot(directory, &GitLab::from_env()?),
@@ -484,6 +487,27 @@ fn unfreeze(directory: impl AsRef<Path>, args: &SourceArgs) -> Result<()> {
     Ok(())
 }
 
+fn show(directory: impl AsRef<Path>, name: Option<String>) -> Result<()> {
+    let mut sources = Sources::read(&directory)?;
+
+    match name {
+        Some(name) => {
+            let Some(source) = sources.get_mut(&name) else {
+                bail!("Source {name} doesn't exist")
+            };
+
+            println!("{name}:\n{source}");
+        }
+        None => {
+            for (name, source) in sources.iter() {
+                println!("{name}:\n{source}");
+            }
+        }
+    }
+
+    Ok(())
+}
+
 fn bot(directory: impl AsRef<Path>, forge: &impl Forge) -> Result<()> {
     let base_ref = git::current_rev(&directory)?;
 
diff --git a/rust/lon/src/sources.rs b/rust/lon/src/sources.rs
index 6ec01ad..c96cba5 100644
--- a/rust/lon/src/sources.rs
+++ b/rust/lon/src/sources.rs
@@ -1,4 +1,8 @@
-use std::{collections::BTreeMap, path::Path};
+use std::{
+    collections::{BTreeMap, btree_map::Iter},
+    fmt,
+    path::Path,
+};
 
 use anyhow::{Context, Result, bail};
 use nix_compat::nixhash::NixHash;
@@ -128,6 +132,11 @@ impl Sources {
     pub fn names(&self) -> Vec<&String> {
         self.map.keys().collect()
     }
+
+    /// Return an iterator over the sources
+    pub fn iter(&self) -> Iter<'_, String, Source> {
+        self.map.iter()
+    }
 }
 
 #[derive(Clone)]
@@ -207,6 +216,22 @@ impl Source {
     }
 }
 
+impl fmt::Display for Source {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        match self {
+            Source::Git(s) => {
+                write!(f, "  Type: Git\n{s}")
+            }
+            Source::GitHub(s) => {
+                write!(f, "  Type: GitHub\n{s}")
+            }
+            Source::Tarball(s) => {
+                write!(f, "  Type: Tarball\n{s}")
+            }
+        }
+    }
+}
+
 #[derive(Clone)]
 pub struct GitSource {
     url: String,
@@ -221,6 +246,19 @@ pub struct GitSource {
     frozen: bool,
 }
 
+impl fmt::Display for GitSource {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        [
+            ("Url", &self.url),
+            ("Branch", &self.branch),
+            ("Revision", &self.revision.as_str().into()),
+            ("Frozen", &self.frozen.to_string()),
+        ]
+        .iter()
+        .try_for_each(|(k, v)| writeln!(f, "  {k}: {v}"))
+    }
+}
+
 impl GitSource {
     pub fn new(
         url: &str,
@@ -349,6 +387,19 @@ pub struct GitHubSource {
     frozen: bool,
 }
 
+impl fmt::Display for GitHubSource {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        [
+            ("Repository", &format!("{}/{}", &self.owner, &self.repo)),
+            ("Branch", &self.branch),
+            ("Revision", &self.revision.as_str().into()),
+            ("Frozen", &self.frozen.to_string()),
+        ]
+        .iter()
+        .try_for_each(|(k, v)| writeln!(f, "  {k}: {v}"))
+    }
+}
+
 impl GitHubSource {
     pub fn new(
         owner: &str,
@@ -485,6 +536,17 @@ pub struct TarballSource {
     frozen: bool,
 }
 
+impl fmt::Display for TarballSource {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        if let Some(origin) = &self.origin {
+            writeln!(f, "  Origin: {origin}")?;
+        }
+        [("Locked", &self.url), ("Frozen", &self.frozen.to_string())]
+            .iter()
+            .try_for_each(|(k, v)| writeln!(f, "  {k}: {v}"))
+    }
+}
+
 #[derive(Clone)]
 struct TarballFlakeRef {
     url: String,