I'll brefase this by saying I'm not an expert on the lore so I might have made a fundamental misunderstanding, but to my knowledge it is commonly believed Netwatch created and is maintaining the Blackwall but in the DLC during the Reed ending there's a quick little blurb on screen during a briefing about the Blackwall that according to the FIA says they didn't actually and don't know how it got there but just one day it popped up. I haven't seen this mentioned anywhere else and the consensus seems to be that Netwatch made it with the help of some AIs so is the FIA wrong or is it a coverup by Netwatch to make people believe they know what happened?