If the badge below is green, then typescript-bot has been active on DefinitelyTyped some time in the last two hours:
typescript-bot-watchdog reports on recent activity by typescript-bot, but only on the DefinitelyTyped repo. The watchdog just checks the time of the first event from typescript-bot's feed.
The watchdog pays attention to two kinds of data from DefinitelyTyped PRs: the date and the filenames. It could also use the declared version number from the header, but does not currently.
I haven't checked whether the activity feed orders events most recent first. It would be super weird if it didn't.