It seems that Steam has a new feature which allows gamers to request access to beta tests of games right from the store page. 

The process of getting access to a beta test usually involves a lot of effort, with sign-up forms and user requests being handled by devs who then have to give out access manually.

This new update streamlines that process by letting users request access easily from the Steam store. Valve is giving developers the power to a Steam Playtest sign-up button on the main listing for their game on the Steam store. 

This button then lets fans or enthusiastic gamers request access to test versions of the games without the hassle of going to a separate website. It also means that developers can easily control access to any tests - including how many players are able to join and when the test will finish. 

For the average gamer, clicking that button on a store page will put you on a waiting list. The game developers can then grant access in batches according to the capacity to handle the requests. Once access is granted, you'll be able to play. 

Valve has also put thought into this setup. Despite the playtest being accessed from the game's main store page, it is treated as separate from the main game.

At a basic level, a user's time playing the playtest won't be counted towards the actual fully released game. Similarly, players who have only been involved in the playtest cannot leave a review for the actual game. Meaning an unfinished game cannot be review bombed before it's even been released.