diff --git a/weboob/backend.py b/weboob/backend.py
index c3cd393c..614db568 100644
--- a/weboob/backend.py
+++ b/weboob/backend.py
@@ -23,6 +23,7 @@ class Backend:
     MAINTAINER = '<unspecifier>'
     EMAIL = '<unspecified>'
     VERSION = '<unspecified>'
+    LICENSE = '<unspecified>'
 
     def __init__(self, weboob):
         self.weboob = weboob
diff --git a/weboob/backends/aum/backend.py b/weboob/backends/aum/backend.py
index 2e3c6c7d..2571de0f 100644
--- a/weboob/backends/aum/backend.py
+++ b/weboob/backends/aum/backend.py
@@ -22,6 +22,11 @@ from weboob.backend import Backend
 from weboob.capabilities.messages import ICapMessages, ICapMessagesReply
 
 class AuMBackend(Backend, ICapMessages, ICapMessagesReply):
+    MAINTAINER = 'Romain Bignon'
+    EMAIL = 'romain@peerfuse.org'
+    VERSION = '1.0'
+    LICENSE = 'GPLv3'
+
     def __init__(self, weboob):
         Backend.__init__(self, weboob)
 
diff --git a/weboob/backends/canaltp/backend.py b/weboob/backends/canaltp/backend.py
index 4f05c8d6..f46cd0ab 100644
--- a/weboob/backends/canaltp/backend.py
+++ b/weboob/backends/canaltp/backend.py
@@ -27,6 +27,7 @@ class CanalTPBackend(Backend, ICapTravel):
     MAINTAINER = 'Romain Bignon'
     EMAIL = 'romain@peerfuse.org'
     VERSION = '1.0'
+    LICENSE = 'GPLv3'
 
     def __init__(self, weboob):
         Backend.__init__(self, weboob)
diff --git a/weboob/backends/dlfp/backend.py b/weboob/backends/dlfp/backend.py
index eb3b84a7..3f6b0b18 100644
--- a/weboob/backends/dlfp/backend.py
+++ b/weboob/backends/dlfp/backend.py
@@ -27,6 +27,7 @@ class DLFPBackend(Backend, ICapMessages, ICapMessagesReply, ICapUpdatable):
     MAINTAINER = 'Romain Bignon'
     EMAIL = 'romain@peerfuse.org'
     VERSION = '1.0'
+    LICENSE = 'GPLv3'
 
     def __init__(self, weboob):
         Backend.__init__(self, weboob)
diff --git a/weboob/backends/transilien/backend.py b/weboob/backends/transilien/backend.py
index fdd7c702..47ce9b9f 100644
--- a/weboob/backends/transilien/backend.py
+++ b/weboob/backends/transilien/backend.py
@@ -28,6 +28,7 @@ class TransilienBackend(Backend, ICapTravel):
     MAINTAINER = u'Julien Hébert'
     EMAIL = 'juke@free.fr'
     VERSION = '1.0'
+    LICENSE = 'GPLv3'
 
     def __init__(self, weboob):
         Backend.__init__(self, weboob)