I haven’t encountered issues with sites because of the ‘API-Killer-IndexedDB’ extension, is it because sites have other means to determine if a user is in private browsing mode than the only IndexedDB status? No idea, but this is interesting. I’ll have to test the ‘Hide Private Mode’ extension to see if it manages to bypass what is performed with ‘API-Killer-IndexedDB’ without actually opening the door closed by the latter. This corroborates the article’s “The Firefox extension Hide Private Mode disables the workaround (that uses the IndexedDB API).”. I don’t use Firefox’s private browsing mode but I do run an extension called ‘API-Killer-IndexedDB’ which “kills HTML5′ IndexedDB API” and interestingly enough when checking Private Browsing Mode on the ‘Device Info’ site mentioned in the article, my Firefox is checked as using private browsing mode disabling ‘API-Killer-IndexedDB’ shows that I’m not using private browsing. The fix offered temporary protection against the detection only as new workarounds were soon discovered and implemented by sites. Google closed a loophole in Chrome 76 that allowed sites to detect if the browser's Incognito Mode was used. Developers found loopholes to detect if private browsing mode (or Incognito Mode) was used, and some magazines may block access to the entire site if the mode is detected.

Private browsing mode bypasses this as it prevents the permanent setting of cookies.

Many newspaper and magazine sites that paywall content use cookies to determine how many free articles a visitor read to allow or block access to the content. Browsing data or cookies are not stored in that mode among other things. Private browsing mode is a special mode of web browsers that blocks certain data from being saved to the local system. Hide Private Mode is a brand new extension for the Firefox web browser that closes a private browsing mode detection loophole that sites use to detect if the browser is in private browsing mode.

Disable private browsing firefox