Everything #OpenStreetMap related is welcome: software releases, showing of your work, questions about how to tag something, as long as it has to do with OpenStreetMap or OpenStreetMap-related software.
OpenStreetMap is a map of the world, created by people like you and free to use under an open license.
Join OpenStreetMap and start mapping: https://www.openstreetmap.org.
There are many communication channels about OSM, many organized around a certain country or region. Discover them on https://openstreetmap.community
https://mapcomplete.org is an easy-to-use website to view, edit and add points (such as shops, restaurants and others)
https://learnosm.org/en/ has a lot of information for beginners too.
I found this kind of cycle barrier in Oldenburg right here:
There are 2-3 similar barriers in the same region.
Problem: there is no design specified in openstreetmap fitting for those. How can this be solved?
(I mean the list below "Types / designs of cycle barriers" here: Cycle barrier in OSM Wiki )
My guess is that isn't a cycle barrier at all. For me it seems to be a special form of removable or foldable bollard for blocking two track vehicles but allows emergence vehicles to open them.