Doing an update on the command line a "wrong" repository (appstorev23) appears:

$ sudo apt update
Hit:1 https://ftp.fau.de/deepin/beige crimson InRelease
Hit:2 https://community-packages.deepin.com/beige crimson InRelease
Hit:3 https://community-packages.deepin.com/driver-25 snipe InRelease
Hit:4 https://app-store-files.uniontech.com/251208144926536/appstorev23 crimson InRelease
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
All packages are up to date.

The issue is that the repository is not on /etc/apt/sources.list and is not on /etc/apt/sources.list.d/

The contents of /etc/apt/sources.list.d/appstore.list are completely different:

$ cat  /etc/apt/sources.list.d/appstore.list
# Written by deepin-home-appstore-client 
deb https://com-store-packages.uniontech.com/appstore-V25 crimson appstore

Searching /etc there is no mention of appstorev23 on any file, and the same thing happens on $HOME.

What can I do?

Many thanks.