RSS and Atom feeds are fetched periodically by the ooh.directory feed crawler.
This identifies itself with a User-Agent string that contains OohDirectory/1.0. For example:
OohDirectory/1.0 (+https://ooh.directory: 1 subscribers)
The frequency of requests for a single feed varies depending on an estimate of how frequently new items appear in the feed. With each request, if there are no new items, then the frequency is reduced. Conversely, if there is a new item, the frequency is increased.
Currently a single feed is requested at most once per hour, and at a minimum once per 24 hours.