The reply is "it depend on your needs":

- .so files from libs folder are native code. Even if not much optimized you should include the armeabi and x86 files removing the v7a and x64 optimization.

For sure you could delete mips architecture that has never been adopted on diffused devices.

From asset folder there a a lot of files that are concerning fonts and chars decoding:

- you could remove font files: that's true if you will distribute only PDF files embedding fonts

- you could remove cmap and umap files if your application won't support chinese, japanese and oriental fonts mapping.

Hope that could help you.