signal-desktop 0 -> 1
attrpath: signal-desktop
Checking auto update branch...
[version] 
[version] skipping because derivation has updateScript
[rustCrateVersion] 
[rustCrateVersion] No cargoSha256 or cargoHash found
[golangModuleVersion] 
[golangModuleVersion] Not a buildGoModule package with vendorSha256 or vendorHash
[npmDepsVersion] 
[npmDepsVersion] No npmDepsHash
[updateScript] 
[updateScript] Success
[updateScript] this derivation will be built:
  /nix/store/12i0vf5v8hnw0a4228dbyhcxrfkdkbs2-packages.json.drv
building '/nix/store/12i0vf5v8hnw0a4228dbyhcxrfkdkbs2-packages.json.drv'...

Going to be running update for following packages:
 - signal-desktop-6.42.1

Press Enter key to continue...
Running update for:
 - signal-desktop-6.42.1: UPDATING ...
 - signal-desktop-6.42.1: DONE.

Packages updated!

Diff after rewrites:
diff --git a/pkgs/applications/networking/instant-messengers/signal-desktop/signal-desktop.nix b/pkgs/applications/networking/instant-messengers/signal-desktop/signal-desktop.nix
index 970deb4c8adb..f9afe7b680fa 100644
--- a/pkgs/applications/networking/instant-messengers/signal-desktop/signal-desktop.nix
+++ b/pkgs/applications/networking/instant-messengers/signal-desktop/signal-desktop.nix
@@ -2,7 +2,7 @@
 callPackage ./generic.nix {} rec {
   pname = "signal-desktop";
   dir = "Signal";
-  version = "6.42.1";
+  version = "6.43.1";
   url = "https://updates.signal.org/desktop/apt/pool/s/signal-desktop/signal-desktop_${version}_amd64.deb";
-  hash = "sha256-6X2+kvqijNq2KsWQ9o4+y2ACDfAd6eeNqVqpDOoqZgs=";
+  hash = "sha256-mDxZFs+rI2eHkkvkmflras1WqBa/HBVBDpdk9NKaC2E=";
 }

No auto update branch exists
There might already be an open PR for this update:
- signal-desktop: 6.42.1 -> 6.43.1; signal-desktop-beta: 6.43.0-beta.1 -> 6.44.0-beta.1
  URL "https://api.github.com/repos/NixOS/nixpkgs/issues/278707"