LandLock is a Minor LSM intended for software developers. They incorporate it into their source code to limit where the programs may read/write. Here's a simple Go example:

    package main

    import (
     "flag"
     "fmt"
     "github.com/landlock-lsm/go-landlock/landlock"
     "io/ioutil"
     "log"
     "os"
    )

    // simple program that demonstrates how landlock works in Go on Linux systems.
    // Requires 5.13 or newer kernel and .config should look something like this:
    // CONFIG_SECURITY_LANDLOCK=y
    //  CONFIG_LSM="landlock,lockdown,yama,loadpin,safesetid,integrity,apparmor,selinux,smack,tomoyo"
    func main() {
     var help = flag.Bool("help", false, "landlock-example -f /path/to/file.txt")
     var file = flag.String("f", "", "the file path to read")

    flag.Parse()
     if *help || len(os.Args) == 1 {
      flag.PrintDefaults()
      return
     }
    
    // allow the program to read files in /home/user/tmp
     err := landlock.V1.RestrictPaths(landlock.RODirs("/home/user/tmp"))
     if err != nil {
     log.Fatal(err)
     }
    
    // attempt to read a file
     bytes, err := ioutil.ReadFile(*file)
     if err != nil {
     log.Fatal(err)
     }
    
    fmt.Println(string(bytes))
    }

Yup. In the application code itself is where landlock shines at the moment.

It's becoming increasingly usable as a wrapper for untrusted applications as well.