Summary
The file Casks/hyprnote@nightly.rb in fastrepl/homebrew-hyprnote still exists but its internal token was updated to char@nightly, causing a mismatch that breaks all brew search commands.
Error
$ brew search gh
Error: Cask 'hyprnote@nightly' definition is invalid: Token 'char@nightly' in header line does not match the file name.
Cause
During the rename from Hyprnote to Char, hyprnote@nightly.rb was updated to declare cask "char@nightly" instead of being removed. The correct char@nightly.rb already exists alongside it.
Fix
Delete Casks/hyprnote@nightly.rb from the fastrepl/homebrew-hyprnote tap — it's a leftover that duplicates char@nightly.rb.