I would like to provide a URL to a subfolder of a GitHub repo in a paper I am about to submit. I thought the link should look like github.com/account/reponame/folder/subfolder, but I realised now that when navigating through the repo, I need to write github.com/account/reponame/tree/main/folder/subfolder for the link to work. Can I assume a link with this format to be persistent, or is there a better way of ensuring that the URL is useful for a long time?