Newer fish packages don't read completions from
/usr/share/fish/completions anymore (see
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1121418).

Please install the completion file in
/usr/share/fish/vendor_completions.d instead.
--- debian/install.ori	2023-01-13 12:03:45.000000000 +0000
+++ debian/install	2025-11-26 13:24:48.665125775 +0000
@@ -1,3 +1,3 @@
 scripts/completions/bash/ytcc.completion.sh /usr/share/bash-completion/completions
-scripts/completions/fish/ytcc.fish /usr/share/fish/completions
+scripts/completions/fish/ytcc.fish /usr/share/fish/vendor_completions.d
 scripts/completions/zsh/_ytcc /usr/share/zsh/vendor-completions


Thanks,
Gian Piero.