With the latest WebKit Nightly Build 258259@main running on macOS 13.1, regex lookbehind is still not working. Test websites: 1. https://javascript.info/regexp-lookahead-lookbehind 2. https://russiaslosses.netlify.app 3.https://www.w3docs.com/learn-javascript/lookahead-and-lookbehind.html Inspector denotes the following error: "SyntaxError: Invalid regular expression: invalid group specifier name" on the part of regex lookbehind from all three websites above. It's reproducible on the latest Nightly Build of Epiphany Canary (GNOME Web using the WebKit Nightly Build) on Linux as well.
The websites you've linked seem to work on latest trunk build for me. There might be a setting that might be disabled in the builds you're trying? Although I think it should be enabled by default.
It seems like a problem from my end. Itβs working on my Windows build. I then found that Epiphany Canary on Linux is not using the latest WebKit Build through WebKitGTK. Will check on the settings on macOS build now.
Marking resolved for now, but please reopen if this doe reproduce with latest WebKit.