I have Fedora 20 setup with default kernel configuration, where bridge feature is enabled as a module (`CONFIG_BRIDGE=m`), and the bridge module loads as the system starts. I don't understand who initiates it, since I have not found anything about `bridge.ko` in `/etc/sysconfig/modules/*`. However it ends up in the memory and every time I have to 'rmmod' it. 

I would like to prohibit loading of the `bridge.ko` on the start up, yet I still want to manually load/unload `bridge.ko` whenever necessary.

I know it is possible to use the blacklist feature in `/etc/modprobe.d/blacklist.conf`, but can anybody point out who is loading `bridge.ko` in default setup of Fedora 20?