builds.sr.ht/compatibility.md#nixos: default repo

17a873146ab0df176fd4bd24425edd7d288ad0ae in
git.sr.ht/~sircmpwn/builds.sr.ht switched to the make-disk-image.nix
script, which adds a "nixos" root channel. This commit documents the
change.

1 files changed, 20 insertions, 5 deletions

diff --git a/builds.sr.ht/compatibility.md b/builds.sr.ht/compatibility.md
index 0c575fa..3b6a1db 100644
--- a/builds.sr.ht/compatibility.md
+++ b/builds.sr.ht/compatibility.md
@@ -666,14 +666,29 @@ latest stable version and the latest bleeding edge.
 
 The packages array is installed with `nix-env -iA`. Since it's possible to
 specify multiple channels, you must provide the full selection path, for example
-`nixpkgs.hello`. Note that the `nixpkgs` channel is **not** added by default.
+`nixos.hello`.
 
 **repositories**
 
-To add custom channels, use `repo-name: channel-url`. The repo name is relevant,
-since `repo-name: repo-url` will execute the commands `nix-channel --add
-repo-url repo-name` and `nix-channel --update repo-name`. Given the nature of
-nix, no channels are added by default.
+To add custom channels, use `channel-name: channel-url`. The channel name is relevant,
+since `channel-name: channel-url` will execute the commands `nix-channel --add
+channel-url channel-name` and `nix-channel --update channel-name`.
+
+Example:
+
+```yaml
+repositories:
+  nixpkgs: https://nixos.org/channels/nixpkgs-unstable
+```
+
+By default, no user channels are present.
+However, like in a fresh NixOS installation, there is a root channel named
+`nixos` set to
+
+* `https://nixos.org/channels/nixos-XX.YY` in `nixos/latest` and `nixos/XX.YY`
+* `https://nixos.org/channels/nixos-unstable` in `nixos/unstable`
+
+which is the channel the image was built from.
 
 ## OpenBSD