Getting “fatal: repository not found” when “git clone” a URL

This must be something basic but I can’t figure it out. I have a github URL that has the form “https://…/tree/main”. How do I download the contents? In response to

git clone https://.../tree/main

I get

fatal: repository 'https://.../tree/main/' not found

When I do

git clone https://.../

I get the contents of the root folder but not the subfolder that I want.

What am I doing wrong?