Regular expressions in "Find in page"

[steel835]

Regex checkbox in "Find In Page" tool.

It would be cool for power users to be able to search text patterns instead of exact matches.

It can be limited to EcmaScript implementation and have a warning tooltip about performance, but I think power users will be glad to see that they can search specific patterns on some pages (some codes with variable characters, multiple variations of phrases, different wordings, etc).

[omentic]

I would love to see support for this. The built-in Firefox search I don't believe extensions have the ability to customize, sadly, so all existing third-party solutions I've seen have to ship their own bespoke find interfaces.