Firefox dev here – do you have an example page? We worked a lot on source maps, so things should have improved but maybe you hit a regression.
112 karma · joined December 13, 2011
> then manually kill the Chrome tab and I can still run through 1 million console lines smoothly
How does that work with DevTools – closing the tab and reading logs?
Console log background was worked on by a contributor as its a good first bug.
On Windows it should background update now as well.
Debugger's new threads panel also solves this partially when you pause in a thread.
Are your use cases extensions, workers or iframes?
Latest on Keychain sopport is in https://bugzilla.mozilla.org/show_bug.cgi?id=106400#c130 as WONTFIX due to macOS changes.