What are the folders in the project used for?

I am wondering what all the folders inside my project are for.
The Ardour Manual - Files and Directories Ardour Knows About only tells me about the Exports folder, which is important to get my completed songs. But doesn’t describe the rest

analysis, dead are always empty for me.
Interchange seems to be my imported and recorded audio and midi files.
Peaks is for what my wave forms look like for any given track it seems.
It is only on Linux that I see Externals and Plugins have stuff in them while on Windows I never see anything in these folders.
On linux:
Plugins: has lots of folders which I assume hold state for the plugins
Externals: has the IRS, Soundfonts or models I have used in the plugins

I was having a separate issue where on linux my plugins weren’t remembering sound fonts or externally loaded IRS or models. So I was wondering if I was doing something wrong. And instead of asking for help on that I instead ask why these folders exist and are full on Linux but seemingly not on windows.

Part of why I ask as well is I recently zipped up my projects to back and saw that on windows I can just delete the folders and reopen the project and it seems like everything is the same and ardour recreates the folders on windows. So either there is a difference or I made a terrible mistake in my backups