First of all
Base on my understanding
Segwit : Reduce Transaction Size so more transaction can be made in 1 block
BTU : Increase the block size to 2MB
Segwit2x is the combine of both? Or its some other specification update? I couldn't find any information about the difference on google
Next, what is all those BIPxxx thing? Like BIP100, 148, then we got 18x, there's so many BIP number
Need some declaration for it, Thanks!
BIP stand for Bitcoin Improvement Proposal
You can find BIPxxx thing here
https://github.com/bitcoin/bips/blob/master/README.mediawiki