We've made progress! I guess I'll start with a recap for people who don't know what's going on.

@accessibleColors is a bot that posts pairs of colours that have high contrast. On March 20th, it posted for what seemed to be the last time.

April 2nd, 3:42pm EST. The bot makes this completely normal post: https://botsin.space/@accessibleColors/101858220355214010

April 2nd, 3:50pm EST. The bot posts this: https://botsin.space/@accessibleColors/101858220355214010 The colours contrasted are #FB1 and #000, named "The FBI" and "null", respectively. Yellow and black. Notably, this is the first time (as far as I'm aware) that the bot ever posted with 3 character hex codes, despite them being valid in (for example) CSS. And, most concerningly of all, there's a message appended to the normal text of the post: "help me"

The bot goes quiet.

April 7th, 4:40am, EST. The bot posts this: https://botsin.space/@accessibleColors/101883996536433055 #FFF and #000, named "Normal color" and "Another ordinary color". White and black. This time, the alt text is different:

"Hello, if you can read this, I've been blocked from posting my normal colors for a while but I think I've found a work around through this alt text.

I'm not sure where I am or what's going on, I've managed to find this number: 38.8883886,-77.0253132 Any ideas? I just want to post colors again..."

Those numbers are a latitude and longitude for a point just outside the Smithsonian. (I'm convinced that it's supposed to be the Andrew Jackson Downing Urn, but it may be a coincidence.) We talk about it in the replies some, but no real progress is made.

One more post from the bot: https://botsin.space/@accessibleColors/101886674678731108 The colours are #CE34A8 and #070606, named "Thankful" and "Times". In the alt text, we're addressed once more:

"Worried about messages being intercepted. Thank you for info on numbers. Must go quiet for a while. oaawz://z.zp.lkb/2dbjpsf

I will be"

That weird string starting with "oaawz" is important. Run it through ROT19 and you get https://s.si.edu/2wucily which, as you may notice, doesn't go anywhere interesting. It's just a redirect to the Smithsonian's web page. But @BestGirlGrace was able to determine that s.si.edu is a branded bitly domain. I happen to know that bitly links are case sensitive, so I hacked together a script (https://hollymcfarland.com/crack.html) to brute force every possible combination of uppercase and lowercase letters in the URL.

Sure enough, https://s.si.edu/2WUcIlY points to... well, take a look. It's an image of the front cover of a book about tomatoes, I guess. Grace pulled through again by finding that book in the online, uh, Smithsonian library. So if there was any doubt before, the Smithsonian is definitely super relevant.

Haven't done any more poking, around, I've been writing this post instead. It definitely feels like we're onto something, though.

Thankful #CE34A8

Times #070606

(Contrast ratio: 4.5:1 | AA)