There are two main phone ecosystems: Apple/IOS and Android. They are both highly refined OSes with lots of additional features. In general, they have pretty good feature parity. However, only one of them could be considered an open platform, Android.
One of the big freedoms provided by Android, is the ability to install your own software. I’m sure 99.999% of app installs on Android are from the play store, and that is as it should be, Google is providing a lot of protection to users there. However, if you want to write your own app, or otherwise install something not approved by google, you can still do that.
The other big freedom is that anyone can take the Android operating system and build their own copy. This is a lot of work for most people, but this openness has allowed an amazing team, called Lineage, to build their own distribution of Android. I’ve installed it on many phones where the vendor wasn’t providing security updates anymore (really, only 2-3 years?!? That needs to be fixed!), which lets me keep using that phone’s hardware, in a safe manner, for years longer, saving stuff from the landfill.
FLOSSing for lent 6/40