Proposed BIP for OP_CAT

In the email, the sender, who refers to themselves as "/dev/fd0 floppy disk guy," provides Ethan with a corrected link for an article titled "Multisig on steroids using tree signatures." The sender mentions that the link can be found at https://blog.blockstream.com/en-treesignatures/. The email is sent using Proton Mail secure email service.

Please note that the farewell part of the email has been omitted from this summary.