We now have Repair Text Encoding (a single menu option) in lieu of Text Encoding (with a variety of options).
For edge cases such as this:
– is an extension feasible?
Food for thought
Charset Menu https://addons.thunderbird.net/addon/charset-menu/
- is intended for use with Thunderbird
- can not be added to Firefox 92 on FreeBSD 14.0-CURRENT.
Background
Text Encoding no longer available in the Firefox menu panel | Firefox Help