diff --git a/test/test_alt.py b/test/test_alt.py
index 7303964..b18e6cb 100644
--- a/test/test_alt.py
+++ b/test/test_alt.py
@@ -81,6 +81,7 @@ def test_relative_link(runner, paths, yadm_alt):
 @pytest.mark.usefixtures('ds1_copy')
 @pytest.mark.parametrize('suffix', [
     '##default',
+    '##default,e.txt', '##default,extension.txt',
     '##o.$tst_sys', '##os.$tst_sys',
     '##d.$tst_distro', '##distro.$tst_distro',
     '##c.$tst_class', '##class.$tst_class',
diff --git a/yadm b/yadm
index 0f57df4..5851a25 100755
--- a/yadm
+++ b/yadm
@@ -177,6 +177,10 @@ function score_file() {
     label=${field%%.*}
     value=${field#*.}
     [ "$field" = "$label" ] && value="" # when .value is omitted
+    # extension isn't a condition and doesn't affect the score
+    if [[ "$label" =~ ^(e|extension)$ ]]; then
+      continue
+    fi
     score=$((score + 1000))
     # default condition
     if [[ "$label" =~ ^(default)$ ]]; then
diff --git a/yadm.1 b/yadm.1
index ae8b778..3212a3a 100644
--- a/yadm.1
+++ b/yadm.1
@@ -527,6 +527,11 @@ and trimming off any domain.
 .TP
 .B default
 Valid when no other alternate is valid.
+.TP
+.BR extension , " e
+A special "condition" that doesn't affect the selection process. Its purpose is
+instead to allow the alternate file to end with a certain extension to
+e.g. make editors highlight the content properly.
 .LP
 
 .BR NOTE :