When I tried to flag an off topic question which belongs to http://webapps.stackexchange.com I didn't find that site in Flagging > Closing > Off-Topic > Migration
and I found only 4 sites which will not be a correct site to ask that question. Why I was able to see only 4 sites and why http://webapps.stackexchange.com was not there?
1 Answer
You can flag it as "needs moderator attention" and put in a custom reason such as "migrate to webapps". Moderators have the ability to "write in" sites in addition to the four that you get to choose.