Currently, every time that Rhino is built, different jar files are produced even for the same set of code. Which could be an annoyance if the packages were posted to additional Maven repositories (for example a wokflow that posted to Github packages), because the digests of those files would be different.

I'd suggest configuring the Gradle build for reproducible jar files, which would imply removing the Built-Dateand Built-Time fields from MANIFEST.MF.

I'd also copy the LICENSE.txt file into the META-INF directory of each jar file (the license is currently being copied to the root directory of the main rhino-<version>.jar file, and not the others).