Vrakfall [1] filed a orphan request for android-sources [2]:
This packaged is flagged out-of-date for more than a year and needs an
update to the API 28 (and it already missed some others). I could
update it myself. I just did it for the fixed versions `android-
sources-27` and `android-sources-28`.
[1] https://aur.archlinux.org/account/Vrakfall/
[2] https://aur.archlinux.org/pkgbase/android-sources/