Great questions, atm the index contains either companies that have their main products as open-source, or companies that make significant contributions (eg: Netflix, Cloudflare, OpenAI have thousands of Github stars).
All jobs should be remote-friendly. There's nothing to do - if you see the jobs, they should be relevant to you.
Some companies do have physical offices (meaning you're welcome to work from there), and those cities are listed if you click on the company's name. Right now it's region-biased per country -- if you scroll to the bottom and click "more" you can change the country. There's def still work to do (visas, non-remote, fine-tuning, etc).
All jobs should be remote-friendly. There's nothing to do - if you see the jobs, they should be relevant to you.
Some companies do have physical offices (meaning you're welcome to work from there), and those cities are listed if you click on the company's name. Right now it's region-biased per country -- if you scroll to the bottom and click "more" you can change the country. There's def still work to do (visas, non-remote, fine-tuning, etc).