Don't rely on RecommendedTBBVersions to create download links
Over at #31307 (moved), we were dealing with a broken GetTor because it made assumptions on the list length available at https://www.torproject.org/projects/torbrowser/RecommendedTBBVersions/. See this comment for more details.
While our emergency fix worked, boklm mentions on IRC that RecommendedTBBVersions is not a good way to learn about the current Tor Browser version:
20:46 boklm│ RecommendedTBBVersions is not a good way to get the current Tor Browser version 20:47 boklm│ https://aus1.torproject.org/torbrowser/update_3/release/downloads.json is better 20:48 boklm│ for example with: wget -q -O - https://aus1.torproject.org/torbrowser/update_3/release/downloads.json | jq -r .version
Let's use this JSON file instead, and make GetTor more robust.