So it works also by using some cli utility to run my software for example?
https://github.com/Zouuup/landrun
All you gotta do is apply a policy and do a fork() exec(). There is also support in firejail.
Also, it's very easy to write your own LandLock policy in the programming language of your choice and wrap whatever program you like rather than downloading stuff from Github. Here's another example in Go:
package main
import (
"fmt"
"github.com/landlock-lsm/go-landlock/landlock"
"log"
"os"
"os/exec"
)
func main() {
// Define the LandLock policy
err := landlock.V1.RestrictPaths(...)
// Execute FireFox
cmd := exec.Command("/usr/bin/firefox")
}