alpha и stable - the same install zip?

zfc

Let's say a release went to alpha channel, user downloaded it, and then this release reached stable channel. When he re-downloads the same release, but from stable channel, will he download the same file, or will there be some changes (in install zip), e.g. bugfixes?

Dumdum

zfc When he re-downloads the same release

Users will not "re-download the same release". Release channels are for distribution of updates, they are not different versions of updates.

Watermelon

zfc I'll copy what I wrote a short while ago to someone else:
"Releases are not exactly experimental, rather everyone (in the Stable (default) update channel, Beta update channel, and Alpha update channel) receives the exact same OTA update package regardless of channel, but the OTA update is moved gradually, first it reaches the Alpha channel, then Beta, and then Stable, unless the GrapheneOS team decides to pause this process due to discovered issues."
https://discuss.grapheneos.org/d/24545-wanting-clarification-of-a-couple-of-things/11

Edit: To answer your question more directly, not only would there be no further bug fixes for the same version offered in the Stable channel, but as far as I know the OTA update package file should be 100% identical. The releases page on the website links to the files for each channel, you should be able to see that the links point to the same URLs. Edit 2: This should apply also to the install files, not only OTA updates.