To write a script that checks out upstream code and compiles it locally is not a distribution by a 3rd party. The code comes directly from Stenzek. That’s why he puts the Arch check there.
If that script happens to do a search and replace of archlinux with some random jibberish (so the check is no longer for archlinux), that’s still not a distribution of modified code because all code modifications happen locally.
To write a script that checks out upstream code and compiles it locally is not a distribution by a 3rd party. The code comes directly from Stenzek. That’s why he puts the Arch check there.
If that script happens to do a search and replace of archlinux with some random jibberish (so the check is no longer for archlinux), that’s still not a distribution of modified code because all code modifications happen locally.