Extremely featureful debuggers such as this one tend to require a great deal of code that is hardware-specific, in addition to being OS-specific. I assume MacOS was targeted first because it's the platform with the greatest degree of hardware uniformity. I fully expect Linux support to materialize someday, but with the caveat that I expect it will only (officially) work with the most popular hardware.
That's right. The only way to have a performant recording is to capture the browser's OS system calls in the recording. This unfortunately makes the feature quite OS specific.
Replay is currently in the user-research validation phase. We care about cross platform support and will prioritize it when we are ready to commit to the feature.
