Mozilla Firefox 60, an upcoming version of the popular web browser that is expected to be released in May, will disable the W3C Proximity and Ambient Light APIs.
The Proximity Sensor API gives applications the ability to monitor the presence of nearby objects without physical contact and the Ambient Light Sensor API allows applications to monitor the ambient light level or illuminance of the device’s environment. Both can be used by applications to make adjustments, such as making modifications to an interface when lighting changes.
Firefox 60 will retain support for both APIs but they will be disabled by default and users wanting to enable them will have to do so manually using Firefox's about:config settings page.
The reason Mozilla engineers opted to disable these APIs, which are relatively new, is that a recent research reports suggests hackers and advertisers could abuse the Proximity Sensor API to determine the position of objects near a smartphone or tablet and take advantage of the Ambient Light Sensor API to steal and/or access browser data without user knowledge.