notification/notification_app.h: No such file or directory

[Anonymous3-a]

(I'm very new to the Flipper Zero, forgive me if I skipped over something obvious)
When I compile FlipperNightStand (by using ufbt) I always get this message:

scons: Entering directory `/home/[username]/.ufbt/current/scripts/ufbt'
        CC      /home/[username]/FlipperZero/FlipperNightStand/clock_app.c
        CDB     /home/[username]/FlipperZero/FlipperNightStand/.vscode/compile_commands.json
/home/[username]/FlipperZero/FlipperNightStand/clock_app.c:8:10: fatal error: notification/notification_app.h: No such file or directory
    8 | #include <notification/notification_app.h>
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
scons: *** [/home/[username]/.ufbt/build/nightstand/clock_app.o] Error 1

How do I fix this? I know where to find the libraries, do I just have to copy them somewhere?

[Anonymous3-a]

I am using Arch Linux, everything is updated well, I'm using ufbt for compilation. I checked, ufbt is up-to-date.