diff --git a/README.md b/README.md
index d6dcf35..03c0cb9 100644
--- a/README.md
+++ b/README.md
@@ -144,3 +144,11 @@ Or to get help for subcommands e.g.
 provs-desktop.jar ide -h
 provs-server.jar k3s -h
 ```
+## Development & mirrors
+Development happens at: https://repo.prod.meissa.de/meissa/provs
+
+Mirrors are:
+* https://gitlab.com/domaindrivenarchitecture/provs (CI issues and PR)
+* https://github.com/DomainDrivenArchitecture/provs
+
+For more details about our repository model see: https://repo.prod.meissa.de/meissa/federate-your-repos
diff --git a/src/main/kotlin/org/domaindrivenarchitecture/provs/desktop/domain/DesktopService.kt b/src/main/kotlin/org/domaindrivenarchitecture/provs/desktop/domain/DesktopService.kt
index 1080535..778e341 100644
--- a/src/main/kotlin/org/domaindrivenarchitecture/provs/desktop/domain/DesktopService.kt
+++ b/src/main/kotlin/org/domaindrivenarchitecture/provs/desktop/domain/DesktopService.kt
@@ -86,7 +86,7 @@ fun Prov.provisionIdeDesktop(onlyModules: List<String>? = null) {
     } else if (onlyModules.contains(DesktopOnlyModule.VERIFY.name.lowercase())) {
         verifyIdeSetup()
     } else if (onlyModules.contains(DesktopOnlyModule.FIREFOX.name.lowercase())) {
-        installFirefox()
+        installPpaFirefox()
     }
 }
 
@@ -109,7 +109,7 @@ fun Prov.provisionOfficeDesktop(onlyModules: List<String>? = null) {
     } else if (onlyModules.contains(DesktopOnlyModule.VERIFY.name.lowercase())) {
         verifyOfficeSetup()
     } else if (onlyModules.contains(DesktopOnlyModule.FIREFOX.name.lowercase())) {
-        installFirefox()
+        installPpaFirefox()
     }
 }
 
@@ -140,7 +140,7 @@ fun Prov.provisionBasicDesktop(
         provisionKeys(gpg, ssh)
         provisionGit(gitUserName ?: whoami(), gitEmail, gpg?.let { gpgFingerprint(it.publicKey.plain()) })
 
-        installFirefox()
+        installPpaFirefox()
         installGopass()
         configureGopass(publicGpgKey = gpg?.publicKey)
         installGopassJsonApi()
@@ -153,6 +153,6 @@ fun Prov.provisionBasicDesktop(
         configureBash()
         installVirtualBoxGuestAdditions()
     } else if (onlyModules.contains(DesktopOnlyModule.FIREFOX.name.lowercase())) {
-        installFirefox()
+        installPpaFirefox()
     }
 }
diff --git a/src/main/kotlin/org/domaindrivenarchitecture/provs/desktop/infrastructure/Firefox.kt b/src/main/kotlin/org/domaindrivenarchitecture/provs/desktop/infrastructure/Firefox.kt
index 6ce584a..86d7a06 100644
--- a/src/main/kotlin/org/domaindrivenarchitecture/provs/desktop/infrastructure/Firefox.kt
+++ b/src/main/kotlin/org/domaindrivenarchitecture/provs/desktop/infrastructure/Firefox.kt
@@ -1,42 +1,61 @@
 package org.domaindrivenarchitecture.provs.desktop.infrastructure
 
 import org.domaindrivenarchitecture.provs.framework.core.Prov
-import org.domaindrivenarchitecture.provs.framework.ubuntu.filesystem.base.addTextToFile
-import org.domaindrivenarchitecture.provs.framework.ubuntu.install.base.aptInstall
-import java.io.File
+import org.domaindrivenarchitecture.provs.framework.core.ProvResult
+import org.domaindrivenarchitecture.provs.framework.ubuntu.filesystem.base.checkFile
+import org.domaindrivenarchitecture.provs.framework.ubuntu.filesystem.base.createFile
+import org.domaindrivenarchitecture.provs.framework.ubuntu.install.base.aptInstallFromPpa
 
 
 /**
- * Installs non-snap firefox, removing a firefox snap-installation if existing
+ * Installs ppa firefox (i.e. non-snap), removing snap-firefox if existing.
  */
-fun Prov.installFirefox() = task {
+fun Prov.installPpaFirefox() = taskWithResult {
 
-    // inspired by: https://www.omgubuntu.co.uk/2022/04/how-to-install-firefox-deb-apt-ubuntu-22-04
+    // inspired by: https://wiki.ubuntuusers.de/Firefox/Installation/PPA/
 
-    task("remove snap firefox") {
-        if (chk("snap list | grep firefox")) {
-            cmd("snap remove firefox", sudo = true)
-        }
+    val unattendeUpgradesForPpaFirefox = "/etc/apt/apt.conf.d/51unattended-upgrades-firefox"
+
+    val preCondition = checkFile(unattendeUpgradesForPpaFirefox)
+    if (preCondition) {
+        return@taskWithResult ProvResult(true, out = "Firefox already installed with ppa")
     }
 
-    aptInstall("software-properties-common")
-    cmd("add-apt-repository -y ppa:mozillateam/ppa", sudo = true)
+    cmd("sudo apt-get -qy remove firefox", sudo = true)
+    optional {
+        cmd("snap remove firefox", sudo = true)
+    }
 
-    // set prio in order to use ppa-firefox above snap
-    addTextToFile(
-        "\nPackage: *\n" +
-                "Pin: release o=LP-PPA-mozillateam\n" +
-                "Pin-Priority: 1001\n",
-        File("/etc/apt/preferences.d/mozilla-firefox"),
+    createFile("/etc/apt/preferences.d/mozillateam", mozillaTeamFileContent, sudo = true)
+
+    aptInstallFromPpa("mozillateam", "ppa", "firefox")
+
+    createFile(
+        unattendeUpgradesForPpaFirefox,
+        "Unattended-Upgrade::Allowed-Origins:: \"LP-PPA-mozillateam:\${distro_codename}\";\n",
         sudo = true
     )
-
-    addTextToFile(
-        """Unattended-Upgrade::Allowed-Origins:: "LP-PPA-mozillateam:${'$'}{distro_codename}";""",
-        File("/etc/apt/preferences.d/mozilla-firefox"),
-        sudo = true
-    )
-
-    aptInstall("firefox")
-    cmd("apt-get upgrade -y --allow-downgrades firefox", sudo = true)
 }
+
+
+private val mozillaTeamFileContent = """
+    Package: * 
+    Pin: release o=LP-PPA-mozillateam
+    Pin-Priority: 100
+
+    Package: firefox*
+    Pin: release o=LP-PPA-mozillateam
+    Pin-Priority: 1001
+
+    Package: firefox*
+    Pin: release o=Ubuntu
+    Pin-Priority: -1
+    
+    Package: thunderbird*
+    Pin: release o=LP-PPA-mozillateam
+    Pin-Priority: 1001
+
+    Package: thunderbird*
+    Pin: release o=Ubuntu
+    Pin-Priority: -1
+""".trimIndent()
\ No newline at end of file
diff --git a/src/test/kotlin/org/domaindrivenarchitecture/provs/desktop/infrastructure/FirefoxKtTest.kt b/src/test/kotlin/org/domaindrivenarchitecture/provs/desktop/infrastructure/FirefoxKtTest.kt
index 666782f..88b7290 100644
--- a/src/test/kotlin/org/domaindrivenarchitecture/provs/desktop/infrastructure/FirefoxKtTest.kt
+++ b/src/test/kotlin/org/domaindrivenarchitecture/provs/desktop/infrastructure/FirefoxKtTest.kt
@@ -1,32 +1,60 @@
 package org.domaindrivenarchitecture.provs.desktop.infrastructure
 
 import org.domaindrivenarchitecture.provs.framework.core.remote
+import org.domaindrivenarchitecture.provs.framework.ubuntu.filesystem.base.deleteFile
+import org.domaindrivenarchitecture.provs.framework.ubuntu.filesystem.base.fileContainsText
 import org.domaindrivenarchitecture.provs.framework.ubuntu.install.base.checkPackageInstalled
+import org.domaindrivenarchitecture.provs.framework.ubuntu.install.base.isPackageInstalled
 import org.domaindrivenarchitecture.provs.framework.ubuntu.secret.secretSources.PromptSecretSource
 import org.domaindrivenarchitecture.provs.test.defaultTestContainer
 import org.domaindrivenarchitecture.provs.test.tags.ExtensiveContainerTest
+import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Assertions.assertTrue
 import org.junit.jupiter.api.Disabled
 import org.junit.jupiter.api.Test
 
 internal class FirefoxKtTest {
 
-    // Attention: this test does not test full functionality of installFirefox, e.g. does not test
-    // remove snap, as this test runs against a container which does not have snap-firefox installed
+    // Attention: this test does not test full functionality of installPpaFirefox, e.g. does not test
+    // remove snap-firefox, as this test runs against a container, which does have neither snap nor snap-firefox installed
     @ExtensiveContainerTest
     fun installFirefox() {
+        // given
+        val prov = defaultTestContainer()
+
         // when
-        val result = defaultTestContainer().session {
-            installFirefox()
-            checkPackageInstalled("firefox")
+        val result = prov.session {
+            deleteFile("/etc/apt/apt.conf.d/51unattended-upgrades-firefox", sudo = true)
+            deleteFile("/etc/apt/preferences.d/mozillateam", sudo = true)
+            installPpaFirefox()
         }
+        val result2 = prov.installPpaFirefox()
 
         // then
         assertTrue(result.success)
+        assertEquals("Firefox already installed with ppa", result2.out)
+
+        assertTrue(prov.isPackageInstalled("firefox"))
+        assertTrue(
+            prov.fileContainsText(
+                "/etc/apt/apt.conf.d/51unattended-upgrades-firefox",
+                "Unattended-Upgrade::Allowed-Origins:: \"LP-PPA-mozillateam:\${distro_codename}\";\n",
+                sudo = true
+            )
+        )
+        val expectedPolicyLine = Regex("1001? https?://ppa.launchpad(?:content)?.net/mozillateam/ppa/ubuntu")
+        val policy = prov.cmd("apt policy firefox").out
+        assertTrue(
+            policy?.contains(expectedPolicyLine) ?: false,
+            "$expectedPolicyLine was not found in $policy"
+        )
     }
 
+    /**
+     * Tests installing firefox on a remote machine, e.g. a virtual machine
+     */
     @Test
-    @Disabled("Update connection details,then enable and run manually")
+    @Disabled("Update connection details, then enable the test and run manually")
     fun installFirefox_remotely() {
         val host = "192.168.56.123"
         val user = "user"
@@ -39,7 +67,7 @@ internal class FirefoxKtTest {
             /* remove for ssh authentication */
             PromptSecretSource("Remote password for user $user").secret()
         ).session {
-            installFirefox()
+            installPpaFirefox()
             firefoxVersion = cmd("apt list firefox --installed").out ?: ""
             checkPackageInstalled("firefox")
         }