Android mobile idle card dropper?

idlemaster got updated recently by other users, it should be ok https://steamcommunity.com/groups/idlemastery/discussions/0/1694917906674479036/#c1694917906675626057

If those games not dropping cards are Varenje or Basingstoke it's because those games aren't out yet.

To answer that, you don't have to worry as, assuming you have 2FT enabled, it calls upon Valve's official servers and of course you will also be required to enter the Steam Guard code on request.

Your password isn't stored. It gets sent to Valve's servers once and is never used again. Your username and a loginkey used for passwordless log ons are saved locally on your device and used for future log ons.

The reason you don't see Valve's login page is because it's not logging into the Steam website (which doesn't let you idle games). It's logging into the Steam network the same way as the official Steam client. There's no web page for that, AFAIK. When you first open the official Steam client, you will notice it asks for your account credentials through a system dialog rather than the website.

You might notice that, for example, Idle Master does bring up the Steam website. It does this to get the cookies needed to view the Steam badges page, so it can find out how many card drops you have left (Idle Daddy doesn't need to do that, since it is fairly easy to generate those cookies once we are signed into the Steam network). That's all Idle Master needs since it doesn't have to log into the Steam network (it just uses the official Steam client which is already connected)

Hope that explains things well enough.