@zira, you are correct insofar as hello-webpage-based projects do not support .htaccess files. They use lws to serve the site and that doesn’t support htaccess syntax, although there are ways to accomplish the same sorts of things.
Since htaccess an Apache-specific feature, you have to be running Apache for it to work. Projects using a configuration like https://glitch.com/~lamp-poc run apache on startup and htaccess will work just fine in those projects.
@Callum-OKane I don’t know how I missed your follow up; my apologies.
htpasswd can be used to create a proper .htpasswd file for use in your .htaccess. Something like htpasswd -c /path/to/new/htpasswd username will create a new one and prompt for the password for the given username. then you can use /path/to/new/htpasswd in your .htaccess file and it should enable you to use Basic Auth, for example. The new htpasswd location has to not exist for that command to work, so if you wanted it at /app/.htpasswd you’d need to (re)move that file first.
As far as extensionless urls, I think you’re probably looking for something like what’s documented at https://alexcican.com/post/how-to-remove-php-html-htm-extensions-with-htaccess/.
Hope that helps!