EmuServer Of Ragnarok (EOR)
From RO Wiki
EmuServer Of Ragnarok was a Japanese Bulletin-Board System (BBS) which conducted discussions around reverse engineering of Ragnarok Online. It was one of the first places where Ragnarok Online Packet structures were posted, along with people on the board submitting fragments of code, and then eventually entire LZH archives which contained server emulators. It is also where 0052.lzh originated from, which is the predecessor/origin of a large number of server emulators.