Taken from the projects official Twitter they offer more than what is available by said toggle on stock:
They provide a nicer MTE implementation as part of hardened_malloc which uses the standard random tags with a dedicated free tag but adds dynamic exclusion of previous tag and current (or previous) adjacent tags. We also fixed Chromium's integration and will improve PartitionAlloc.
They also use it for their browser too using PartitionAlloc. Other Chromium-based browsers including Chrome don't use MTE since they don't really use the system allocators and have PartitionAlloc MTE disabled.
They are also continuing work on integrating more ARMv9 security features. MTE having the highest impact and being the most interesting of these features, but they're expanding usage of PAC and BTI. Android uses Clang's type-based CFI but not everywhere so BTI is still useful.
They provide a nicer MTE implementation as part of hardened_malloc which uses the standard random tags with a dedicated free tag but adds dynamic exclusion of previous tag and current (or previous) adjacent tags. We also fixed Chromium's integration and will improve PartitionAlloc.
They also use it for their browser too using PartitionAlloc. Other Chromium-based browsers including Chrome don't use MTE since they don't really use the system allocators and have PartitionAlloc MTE disabled.
They are also continuing work on integrating more ARMv9 security features. MTE having the highest impact and being the most interesting of these features, but they're expanding usage of PAC and BTI. Android uses Clang's type-based CFI but not everywhere so BTI is still useful.