Weird behaviour when civicrm.sql.gz in document root

I patched drush (see #16541) and check it I made a dump to my test server's document root:

drush civicrm-sql-dump --gzip --result-file=civicrm.sql

result is a correct dump file in a not very safe location. However that is not everything. I discovered that the file in the particular path causes a weird side effect. I clicked the usual CiviCRM link in my admin_menu bar, that links to the path /civicrm?reset=1 To my surprise it does not show the usual CiviCRM dashboard but it will start downloading the uncompressed sql dump, the browser apparently decompressing it. With some experimenting I discover that anything with file name civicrm will at least cause dashboard load to fail and when it is gz compressed it will download.

Probably a less urgent bug but clicking the CiviCRM link should under all circumstances only show its dashboard, no matter what I load in the document root.