(looks like I can’t respond in the thread at Has the Brave browser been removed from Manjaro repositories?, can’t mention more than 2 people and can’t include any links in my post)
I’d like to address the original question.
An overview of all published Brave browser versions can be found at https://versions.brave.com/. This page is meant for human consumption.
For each channel/platfrom/architecture combination, there are individual endpoints returning the current internal and public version. Those are meant to be used in automation.
For instance https://versions.brave.com/latest/release-linux-x64.version returns the current public release channel version for linux x64 and https://versions.brave.com/latest/nightly-linux-arm64.version returns the latest public nightly channel version for linux arm64.
More information can be found on the overview page.
Hope this helps and please feel free to ask questions here, or on the Brave support forums.
PS. One thing that may not be obvious is the distinction between internal and public releases. Internal releases are only made available via GitHub and are meant primarily for testing, rather than distribution to end users. Anyone (re)packaging the browser should stick to public releases, unless the package is specifically meant for less stable releases.