Fingerprints, which don’t require users to opt-in as they do with cookies, track people based on the characteristics of a computer. As noted by Techdows, these can include screen resolution, browser, timezone, language, installed extensions and fonts, and the operating system. The information is then used to create a unique profile—a fingerprint—that is used to track users across websites.
On January 7, 2020, Mozilla will release Firefox 72, which privacy advocates should appreciate as it blocks fingerprints automatically on any sites being visited using its Enhanced Tracking Protection feature.
The current Firefox 70 blocks several unwelcome web features by default, including social media trackers, cross-site tracking cookies, tracking content in private windows, and Cryptominers.
For those who don’t want to wait until next year to access the feature, it can be enabled now though the Custom setting in Firefox's Enhanced Tracking Protection. This can be accessed by selecting options in the Firefox menu, clicking on Privacy and Security, setting Enhanced Tracking Protection to Custom, and ticking the Fingerprints box.
It’s noted that enabling fingerprint blocking could break some websites or cause their appearance to change. Mozilla says it will be conducting future tests to find ways of avoiding these issues.