If you're someone who takes their digital security seriously, you've no doubt got unique passwords for all of your accounts, use password managers, and when possible, two-factor authentication. Steam offers such systems which can really help protect it from others, but if you want to see if and when others are trying to get into your account, you can now do so through your account page, which tracks login attempts by you and any nefarious actors out there.
To access this information, you'll need to login to your Steam account on the main account page on the Steam website (not within the Steam client). There you'll find "recent" login information which actually stretches back a full 12 months, so you can double check logins from a few months back if you wish. It also keeps track of any logins through third-party websites, as well as any broadcasts you've watched recently.
As PCGamesN points out, the big reason for these new additions is part of the expansive new GDPR regulation which covers rules on data retention and instils severe fines for companies who fall foul of it. While technically only applicable to EU citizens, most of the companies who are complying with the new regulations have expanded their coverage worldwide to make sure that they don't fall foul of it.
This will likely to lead to an ever-expanding transparency at Valve and within its Steam client so that customers can not only feel well protected by adequate security measures, but that they have a firm understanding of how Valve handles their data.
