As near as I can tell, the 'excuses' element within the yaml data is a

complete duplication of other structured data elsewhere in the yaml, and
does nothing but slow down the yaml parsing.  So, just avoid emitting it.

britney2/utils.py

@@ -368,6 +368,8 @@ def write_excuses(excuselist, dest_file, output_format="yaml"):
         ensuredir(os.path.dirname(dest_file))
         with open(dest_file, 'w', encoding='utf-8') as f:
             edatalist = [e.excusedata() for e in excuselist]
+            for e in edatalist:
+                del(e['excuses'])
             excusesdata = {
                 'sources': edatalist,
                 'generated-date': datetime.utcnow(),