https://hopglass.berlin.freifunk.net
...runs an instance of HopGlass https://github.com/plumpudding/hopglass that gets its data from the openwifimap backend. The OWM data is converted to ffmap/hopglass format using a simple converter (found in owm2ffmap/). The OWM backend is running on the same server, so owm2ffmap just parses its data directory. There's old code that could fetch the OWM data from remote as well.
In case you wonder, node info ends up in OWM since the OWM script (see freifunk-berlin/packages) on the node uploads the data via api.openwifimap.net or util.berlin.freifunk.net about every hour.
See https://wiki.freifunk.net/Berlin:Server#hopglass.berlin.freifunk.net for server details and further links.