FOSDEM is a regular event for open-source projects developers and users. It happens every year in Brussels (late January or early February). Jenkins project regularly participates in this event and organizes additional events around the FOSDEM dates.
The conference will take place on Feb 06-07. As usual, many Jenkins community members plan to participate in the event. This year the event will be virtual, and the format will change. Many traditional events like Jenkins Contributor Summit are likely to be scheduled to other dates. More details will be announced in the coming week.