The database that nRF Connect for Mobile pulls definitions from is significantly out of date (exact age depends on the category)
https://github.com/NordicSemiconductor/bluetooth-numbers-database
This isn't ideal, especially as the repo itself promises that users will be "permanently bet kept up to date":
The #1 question most Bluetooth developers will ask themselves when seeing this repo is a variation along the lines of
Don't need another library - I can write this in 5 minutes. And whilst true, this does not cover the entire picture, because it's everyone writing the same piece of code 5 minutes, and then having to keep it up to date. That's the weight we're removing from you by using this community project. You don't need to worry about staying up to date regarding new Company IDs or GATT Attributes - just write code that pulls information from this repo every once in a while, and your apps will permanently be kept up to date. No need for reinventing the wheel.
While the values are easily available on https://bitbucket.org/bluetooth-SIG/public/src/main/assigned_numbers/, this is not the source used by nRF Connect for Mobile.