MediaWiki:Tags-delete-explanation-in-use/qqq

"It" refers to a tag.

This is the second paragraph (not always shown) of an explanation to tell users what they are about to do. The first paragraph is probably.

Parameters:
 * $1 - the code name of the tag that is about to be deleted
 * $2 - the number of places the tag is used. The value is the sum of (revisions + log entries) where the tag is used.