Multiple adhoc servers have some kind of live status page, where you can see what's being played. Future versions of PPSSPP will be able to display this information in the server browser.
There are currently two standards, but PPSSPP will support data.json going forward.
Examples:
http://psi-hate.com:27315/data.json
Examples:
https://www.socom.cc/status.xml
There's also: http://server:27314/data_debug. which shows internal state.
If you want your data.json page to be shown in ppsspp, contact me on [email protected] with data.json in the subject, and let me know the full URL that will display the data.json. Ideally this will be yourhost:27315/data.json but I'll accept other URLs.
aemu_postoffice already supports :27315/data.json, you just need to expose it on your domain.