Requested feature overview description.

The BUR help should mention that the script can only have 25 lines.
(I don't know if this limit applies to all users, or just to Members; the Help: Accounts page doesn't contain the words BUR, bulk, update or request)
By "BUR help", I mean the "Help" link under the "Script" textbox in https://e621.net/bulk_update_requests/new

Why would it be useful?

So people don't waste time creating BUR scripts with more than 25 lines.

What part(s) of the site page(s) are affected?

https://e621.net/bulk_update_requests/new

+1, the BUR page needs some more explanation in general. It's really not the most intuitive thing for inexperienced users.

+1, and how about an alternative design to the script thingie?

Select a dropdown for the change you wanna do, add a line with a [+] button like on sources in the upload page, and you write only the tags, which can be suggested by the site like in the tag search, preventing typos.

The "add a line" button could be limited to not allow adding another one after 25.

https://i.imgur.com/GD53QoD.png