Misc. Wondering What This Thing Is

[will111t]

Hi all, I am relatively new to CJ’s but I have had a 58 FC for some time. I recently bought a 73 CJ5 and I am going to re-wire it because it is kind of a mess. But there is one thing under the hood that I can’t identify. Can anyone tell me what this thing is? (Photo attached)

Thank you very much!

 

[CJ]

That's a weird pressurized canister (looks like it has a capped schreder valve.) It goes into the cabin through the firewall (black hose.) Where does it connect and where is the red hose going?
It can't be emissions because it goes in the cabin.