diff --git a/maps.py b/maps.py
index f9ae6fad1..d92238b34 100644
--- a/maps.py
+++ b/maps.py
@@ -10,6 +10,7 @@ __module_group__ = "Core"
 
 import os
 from flags import is_float
+from utils import browser_supports_download_filename
 from utils import get_url_from_post
 from utils import acct_dir
 from utils import load_json
@@ -897,7 +898,7 @@ def html_hashtag_maps(base_dir: str, tag_name: str,
         description = period_str
         if translate.get(period_str):
             description = translate[period_str]
-        if 'mozilla' in ua_str_lower or 'firefox' in ua_str_lower:
+        if browser_supports_download_filename(ua_str_lower):
             html_str += '<a href="' + endpoint_str + \
                 '" download="' + tag_name_str + '.kml">' + \
                 description + '</a>'
diff --git a/utils.py b/utils.py
index 70c2ebf55..d78547a8c 100644
--- a/utils.py
+++ b/utils.py
@@ -5277,3 +5277,14 @@ def set_searchable_by(base_dir: str, nickname: str, domain: str,
             fp_search.write(searchable_by)
     except OSError:
         print('EX: unable to write searchableByDropdown ' + filename)
+
+
+def browser_supports_download_filename(ua_str: str) -> bool:
+    """Does the browser indicated by the user agent string support specifying
+    a default download filename?
+    https://developer.mozilla.org/en-US/docs/Web/HTML/Element/a#download
+    https://www.w3schools.com/howto/howto_html_download_link.asp
+    """
+    if 'mozilla' in ua_str or 'firefox' in ua_str:
+        return True
+    return False
diff --git a/webapp_calendar.py b/webapp_calendar.py
index 6df948899..587e5f574 100644
--- a/webapp_calendar.py
+++ b/webapp_calendar.py
@@ -10,6 +10,7 @@ __module_group__ = "Calendar"
 import os
 from datetime import datetime
 from datetime import date
+from utils import browser_supports_download_filename
 from utils import remove_html
 from utils import get_display_name
 from utils import get_config_param
@@ -347,7 +348,7 @@ def _html_calendar_day(person_cache: {}, translate: {},
 
     # icalendar download link
     ua_str_lower = ua_str.lower()
-    if 'mozilla' in ua_str_lower or 'firefox' in ua_str_lower:
+    if browser_supports_download_filename(ua_str_lower):
         default_cal_filename = 'calendar_day.ics'
         calendar_str += \
             '    <a href="' + path + '?ical=true" ' + \
@@ -689,7 +690,7 @@ def html_calendar(person_cache: {}, translate: {},
 
     # calendar download link
     ua_str_lower = ua_str.lower()
-    if 'mozilla' in ua_str_lower or 'firefox' in ua_str_lower:
+    if browser_supports_download_filename(ua_str_lower):
         default_cal_filename = 'calendar_month.ics'
         calendar_icon_str = \
             '    <a href="' + path + '?ical=true" ' + \