Steam’s recently extended account data pages include a detailed history of recent login attempts.
In the wake of the European Union’s GDPR ruling, Steam implemented account data pages to disclose all information held about an account to the user. This made it easier to see what personal information Valve held on its users, alongside letting users review their entire purchase and subscription history.
Three new pages have now been added to the suite of data tools - two of which should be useful for keeping track of account security. Recent Login History gives you the date, time and location of every attempt to log into your Steam account over the last year. Recent Third Party Site Logins gives you similar information, but focussing on Steam login attempts through external sites.
The third new page is less focussed on security, but should help shed more light on the data Steam keeps on its users. Recently viewed broadcasts does what it says on the tin - a list of Steam broadcasts you’ve viewed, if any.
The extensive list of account data pages can be found by logging into Steam and visiting this address.