I was confused because the ones that did work were, when I unzipped them, in a folder called "phpbb"
This all worked because I moved them to
ext/phpbb/extension_name
The ones that didn't work were not in a folder called phpbb, they were in the author's name like you said, and when I included that it worked.
(sorry if this sounds stupid, I'm really tired. it's late where I am)
Anyway, I see what I was doing wrong now. Thank you.
However, this site logo file still doesn't work.
When I unzip it I get a folder called: davidsitelogo-3.2
I move it to
ext/davidsitelogo-3.2
and it doesn't work. There should be another folder with it called "sitelogo" but there isn't. It's just all the files for the extension.
you can see it here:
https://www.phpbb.com/customise/db/extension/site_logo/