They use their own, Linglong. Tho you type apt to use it. I couldn't install anything tho. It has a deb installer but refused to install Chrome or Input Remapper. They use an old version of Chromium. Looks nice tho and respects dark mode. Same slow scrolling so I installed the Linux Scroll Speed Fix extension.
Deepin uses the Debian stable repositories , so not the latest packages. The software store is a Deepin app and worked well when I tried it on a stable version. There are limitations when it comes to customizing the panel applets.
Tried 20.8 in a VM. No driver for my Realtek dongle. Found my printer after I gave it the IP and installed driver but then couldn't find it. Mic works now. Store had an old version of Pinta. Could not install flatpak Pinta or deb Input Remapper. Missing dependancies.
Definitely do not mess with this until 23 comes out.