For signed jars manifest files are often large (e.g. for FX runtime manifest is 100k compressed and 250k uncompressed) and vast majority of space is occupied by list of (name, signature) for all class files.
With recent enhancements in the caching results of security validation this info is often not used for subsequent starts of the same app. In fact majority of application obtain very few details from manifest files
- some of the main attributes and also sealing information for packages (but it is rarely present).
The idea is to keep all but main attributes and package data separately in the cache index file and read them only if they are requested.