Is explained by my Android R branch has not been updated for a while.
I had a run of prebuilts fails (I never found out why) but your log includes other detail which I half remember.
java.util.zip.ZipException: zip END header not found
at java.base/java.util.zip.ZipFile$Source.zerror(ZipFile.java:1535)
at java.base/java.util.zip.ZipFile$Source.findEND(ZipFile.java:1436)
[snip]
at java.base/java.util.jar.JarFile.<init>(JarFile.java:297)
at com.android.signapk.SignApk.main(SignApk.java:1146)
I did a size check with ncdu
ncdu 1.15.1 ~ Use the arrow keys to navigate, press ? for help
----- /prebuilts/prebuiltapks --------------------------------
1.7 GiB [##########] /Browser
356.2 MiB [## ] /MagicEarth
355.4 MiB [## ] /AdvancedPrivacy
84.9 MiB [ ] /BlissLauncher
75.3 MiB [ ] /GmsCore
62.3 MiB [ ] /VOSK
20.9 MiB [ ] /PdfViewer
16.7 MiB [ ] /Apps
15.5 MiB [ ] /AccountManager
14.6 MiB [ ] /PicoTTS
11.6 MiB [ ] /Message
11.1 MiB [ ] /ESmsSync
10.8 MiB [ ] /eDrive
10.3 MiB [ ] /OpenKeychain
9.5 MiB [ ] /Mail
8.8 MiB [ ] /WebCalendarManager
7.6 MiB [ ] /Notes
5.9 MiB [ ] /Camera
5.2 MiB [ ] /SeedVault
4.7 MiB [ ] /Calendar
4.3 MiB [ ] /Light
3.9 MiB [ ] /OpenWeatherMapWeatherProvider
3.8 MiB [ ] /Tasks
3.3 MiB [ ] /eSpeakTTS
2.0 MiB [ ] /DemoApp
1.7 MiB [ ] /NominatimNlpBackend
1.4 MiB [ ] /FakeStore
1.3 MiB [ ] /BlissIconPack
1.0 MiB [ ] /PwaPlayer
104.0 KiB [ ] /DroidGuard
76.0 KiB [ ] /MozillaNlpBackend
32.0 KiB [ ] /GsfProxy
4.0 KiB [ ] README.md
4.0 KiB [ ] .gitattributes
@ 0.0 B [ ] .git
Total disk usage: 2.7 GiB Apparent size: 2.7 GiB Items: 171
I never tried. But we always wait for repo sync completed successfully but prebuilts come on a different path, git-lfs.