Unlike the other per-site metas, Meta Web Apps wasn't included in the October data dump.
All per site metas will be included with their respective parent site.
The admins have stated that sites will only be added to the data dump when they're big enough to contribute meaningfully. Web Apps was just added last go-round, and today it has 2301 questions. Meta Web Apps only has 182 questions. Even if they are planning to include it, it's not big enough yet.