There is work in progress for Lion:

• Bug 636455 – [10.7] Investigate compatibility with Mac OS X 10.7 "Lion"

Thanks cor-el,

But the bug report does not mention the completed progress which I want to know. What has Mozilla DONE so far about Mac OS X Lion compatibility?

Like Google adds support for Mac OS X Lion Fullscreen application mode and Mac OS X Lion Resume feature with Chrome 14.0 and Opera adds support for Mac OS X Lion Fullscreen application mode in Opera 11.51. Both Chrome 14 and Opera 11.51 are expected to be released in August or 1st week of September.

Since Firefox 7 is being released 27 September, I wanted to know what Mac OS Lion features does it add support for. And I also wanted to now what Mac OS X Lion features are currently supported by Firefox 6.0

That bug is a meta bug that has a list of open and resolved (strike through) in the "Depends on" section.
If you hover each bug in the Depends on list then you see a tooltip of what it is about.

Thanks cor-el.

For what it's worth, the gestures part seems to have been resolved in OSX 10.7.2. You can now activate two- or three-finger swipe gestures!