This was introduced this morning.
The intent is the same as "other", with wording that hopefully makes it a bit more clear what flagging should be used for. The nature of the flag and how it is handled are unchanged.
We repeatedly get complaints (on meta and via email) about problems that should be reported to moderators. Simultaneously, moderators (particularly on SO) are frequently frustrated by "other" flags that have more specific flag types (spam, close) or aren't problems moderators can handle in the first place ("i need an answer urgently!").
The hope here is that this change (along with other wording changes made to that dialog) encourages folks to use the proper flag type for problems that have one, and avoid it for problems that don't require moderation at all.
Of course, we'll be monitoring folks' actual behavior to see if this works.