RE: Which table shows Item availability per BIN
Hello MahGah,
If you want see the Item Bin Content for a single item, you can check on Item List page as shown in below image.

And if you need to check all Bin Content availability of all Items at once, you can go to Warehouse Entries as shown below image. Its Page id is 7318 and Table ID is - 7312

You can also check that data on Bin Contents as shown in below image. Its Page id is 7374 and Table ID is - 7302

If my answer helped you, maybe it can help others. Please verify it, so other users know it worked or helped you.
Thank you.