In general discussions about how Android phones might collect location and personal data, the focus often falls on third-party apps rather than Google's built-in apps. This awareness has grown due to numerous apps gathering significant information about users, leading to concerns, especially when targeted ads start appearing. The worry persists about whether apps, despite OS permissions, eavesdrop on private in-person conversations, a concern even addressed by Instagram's head in a 2019 CBS News interview.

However, attention to third-party apps tends to overshadow the fact that Android and its integrated apps track users extensively. While much of this tracking aligns with user preferences, it results in a substantial accumulation of sensitive personal data on phones. Even for those trusting Google with their information, understanding the collected data and its usage remains crucial, especially considering the limited options available to opt out of this data collection.

For instance, a lesser-known feature involves Google Assistant's ability to identify a parked car and send a notification regarding its location. This functionality, primarily guesswork, varies in accuracy and isn't widely publicized by Google, reflecting how tech companies leverage personal data for results that might raise concerns about potential eavesdropping.

The ways Android phones track users were highlighted in an October 2021 Kaspersky blog post referencing a study by researchers from the University of Edinburgh and Trinity College. While seemingly innocuous, the compilation of installed apps, when coupled with other personal data, can reveal intimate details about users, such as their religion or mental health status. This fusion of app presence with location data exposes highly personal information through AI-based assumptions.

Another focal point was the extensive collection of unique identifiers by Google and OEMs, tying users to specific handsets. While standard data collection aids app troubleshooting, these unique identifiers, including Google Advertising IDs, device serial numbers, and SIM card details, can potentially associate users even after phone number changes, factory resets, or ROM installations.

The study also emphasized the potential invasiveness of data collection methods, such as Xiaomi uploading app window histories and Huawei's keyboard logging app usage. Details like call durations and keyboard activity could lead to inferences about users' activities and health, reflecting the extensive and often unnoticed data collection practices by smartphones, as highlighted by Trinity College's Prof. Doug Leith.