Question Build Report - question about contents

I'm trying to reduce my android bundle size and have optimized as much as I could the textures and sounds. This is how my build result currently looks:

Build Report
Uncompressed usage by category (Percentages based on user generated assets only):
Textures 6.5 mb 24.3%
Meshes 0.0 kb 0.0%
Animations 226.3 kb 0.8%
Sounds 752.3 kb 2.8%
Shaders 40.0 kb 0.1%
Other Assets 3.3 mb 12.2%
Levels 3.6 mb 13.6%
Scripts 2.5 mb 9.5%
Included DLLs 9.4 mb 35.4%
File headers 315.9 kb 1.2%
Total User Assets 26.6 mb 100.0%
Complete build size 176.0 mb

I am trying to decrease it further (aiming for 15 MB) however it is not clear to me what the following categories are: Levels, Included DLLs, Other Assets? How can I see these? What are they?

Maybe not everything from these categories is needed or I can remove third party functionality that takes too much space.

I assume Scripts is basically the code, right?

Thanks!