06/10/2019 (Mon) 11:12:12
File/Save Page As...
Or make a screenshot.
Ofc you can't upload back the same, especially with conversations.
If you have image/document/music/site-link/video-link dumps, you can save all those onto your comp.
If you liek certain posts, you can save those into text files and save images too, or just take screenshots.
As for me who write stuff, I write everything in textfiles first and gather pictures I'll upload with the text, so I have everything already anyway.