How do you select a block of text with Vimium?

Almost the same way as in vim ;)

1. Search for the text you want to copy with '/my-search-term' 2. Switch to visual mode with 'v' 3. Select the text you want 4. Yank!

Visual Mode https://github.com/philc/vimium/wiki/Visual-Mode

Note btw that Firefox support something called caret browsing (maybe other browsers as well, but i stick with Firefox if technically possible). Hit F7 and you can navigate around a page using a caret.

I’ve never heard of or used Vimium before. But based on the name, it stands to reason that some variant of the ‘v’ key should select text.