diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 00000000..135dfe33
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,2 @@
+indent_style = tab
+indent_size  = 8
diff --git a/.gitignore b/.gitignore
index 34f8c464..85db1c84 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,6 +1,7 @@
 *.o
 *.so.*
 *.so
+*.a
 *_parse.tab.c
 *_parse.tab.h
 lex.*_parse.c
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index c6cea9a6..fcdf92d9 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -2,12 +2,14 @@
 
 The clixon project welcomes contributions from the community.
 
+## Licensing
+
 A contribution must follow the [CLIXON
 licensing](https://github.com/clicon/clixon/blob/master/LICENSE.md)
-following the dual licensing: either Apache License, Version 2.0 or
+with the dual licensing: either Apache License, Version 2.0 or
 GNU General Public License Version 3.
 
-<!-- A Contributor License Agreement (CLA) such as generated by eg https://contributoragreements.org may need to be signed?-->
+Note especially, the contribution license agreement (CLA) is described in the CLA section of the Apache License, Version 2.0.
 
 ## C style