diff --git a/src/caoscrawler/converters.py b/src/caoscrawler/converters.py
index b307e137d637103f0f37cb9959674c7d1f956d4b..cce5146e466209a28b43b4b2b4a2b500f00b5431 100644
--- a/src/caoscrawler/converters.py
+++ b/src/caoscrawler/converters.py
@@ -53,11 +53,15 @@ from .utils import has_parent
 # by the converters:
 SPECIAL_PROPERTIES = ("description", "name", "id", "path",
                       "file", "checksum", "size")
+# This RE is used to check whether a value is just a single variable:
 SINGLE_VAR_RE = re.compile(r"^\$(\{)?(?P<varname>\w+)(\})?$")
 logger = logging.getLogger(__name__)
 
 
 class CrawlerTemplate(Template):
+    # This adds a dot to the default pattern.
+    # See: https://docs.python.org/3/library/string.html#template-strings
+    # Default flags is re.IGNORECASE
     braceidpattern = r"(?a:[_a-z][_\.a-z0-9]*)"