1. what are so little, tiny vertical QR code like columns sometimes we see in the end of the notes? is it zaps icon? #nostr
2. why do many accounts have url like .com endings after account @ symbol?
Discussion
I dont know about 1, have not see those QR codes.
About 2, is an NIP05 implementation, where you can link your NPUB to a website . If I had access to the back end of cocacola . com I could make my npub Cyberplanta@Cocacola.com
1. It sounds like you may be implying lightning invoices or the QR code for a lightning invoice
2. Nip-05 verification 