Hey, since I am a pretty big fan of history, I wanted to ask what to these flags belong to. Thanks for any answers !
None of those flags have anything to do with hiatory. The left one is a bear flag. Bear as in the gay kind, not animal kind. The right one is the leather pride flag.
If I had a nickel for every time someone posted a manga of Verxina having nightmares about Gentildonna pulling a Narita Top Road on her sisters, I'd have three. Not a whole lot, but still.
So, in this case I happened to recognize the fence and it's color because it's pretty distinctive, and in the context of a jirai kei being there it's not that unexpected. This is corroberated by the other pages in this comic, even though this was the first one that got me to pay attention to it. After realizing it's this park, it's just a matter of checking all sides (one side doesn't have this fence), and post #8136076 also helped locate it in relation to the toilets block.
A popular reaction image used on forums like Something Awful / Facepunch (RIP) / Knockout with a large userbase of people with some connection to Source games like TF2. There has always been a large divide between the pro-anime and anti-anime people in the TF2 community. So whenever the discussion in a thread became "too anime" it's been a tradition for the antis to spam this reaction image.