Question: What is "Request (+1)"?

[abuyoyo]

I'm messing around a bit with rewrite_rules/endpoints/template includes, and came across this.
The Request menu tab is marked Request(+1). What is this indicative of?

[johnbillion]

You're not the first person to ask. The +X number represents the number of non-standard query variables that are present in the request, in your case the bla2 query variable that's highlighted in purple in the Query Vars section.

[abuyoyo]

Perhaps add a title attribute to the button in such cases? - prompting a tooltip on hover: +1 non-standard query variables in request. See Query Vars section