(1) How about adding another file to the META-INF directory which is just
like manifest - just without the line breaks?

That could even be automated.

(2) Also, "jar -i" calculates an index for where which package is ("INDEX.LIST").
Is that also hard-word-wrapped?  The specification
https://docs.oracle.com/javase/7/docs/technotes/guides/jar/jar.html#JAR%20Index
only mentions the 72 Byte limit for "manifest and signature files" and then specifies
Index File Specification separately.

Either would be good enough for the GC retaining the deps, right?