diff --git a/wireshark-mime-package.xml b/wireshark-mime-package.xml
index 01f1c78f99..7493bddd70 100644
--- a/wireshark-mime-package.xml
+++ b/wireshark-mime-package.xml
@@ -1,5 +1,32 @@
 <?xml version="1.0" encoding="UTF-8"?>
 
+<!--
+    This file allows freedesktop.org-compliant desktops (such as GNOME and
+    KDE) to know which files should be opened by what program (and what icon
+    to show for the file in a file browser).
+
+    Both magic and file name glob patterns are supported; glob patterns are
+    preferred since they don't require require opening and reading part of
+    the file to determine its type.
+
+    The specification for this file can be found here:
+    https://standards.freedesktop.org/shared-mime-info-spec/latest/
+
+
+    Note that ideally the MIME types listed here should be IANA-registered:
+
+    https://www.iana.org/assignments/media-types/media-types.xhtml
+
+    If your file type is not registered then using one of the
+    (not-really-a-good-idea and deprecated) x- media types is the only option
+    if you want files to be associated with Wireshark in
+    freedesktop.org-compliant file browsers.
+
+
+    NOTE: if you do add a MIME type here, don't forget to add it to the list
+    of MIME types handled by Wireshark in wireshark.desktop.
+-->
+
 <mime-info xmlns="http://www.freedesktop.org/standards/shared-mime-info">
   <mime-type type="application/vnd.tcpdump.pcap">
     <comment>Packet Capture (PCAP)</comment>
diff --git a/wiretap/file_access.c b/wiretap/file_access.c
index ac383ccc16..61653fc311 100644
--- a/wiretap/file_access.c
+++ b/wiretap/file_access.c
@@ -307,6 +307,17 @@ wtap_get_all_file_extensions_list(void)
  * type to interpret it as, if the file name has no extension, the
  * extension isn't sufficient to determine the appropriate file type,
  * or the extension is wrong.
+ *
+ * NOTE: when adding file formats to this list you may also want to add them
+ * to the following files so that the various desktop environments will
+ * know that Wireshark can open the file:
+ *	1) wireshark-mime-package.xml (for freedesktop.org environments)
+ *	2) packaging/macosx/Info.plist.in (for OS X)
+ *	3) packaging/nsis/AdditionalTasksPage.ini and packaging/nsis/common.nsh
+ *	   (for Windows)
+ *
+ * If your file format has an expected extension (e.g., ".pcap") then you
+ * should probably also add it to file_type_extensions_base[] (in this file).
  */
 static struct open_info open_info_base[] = {
 	{ "Wireshark/tcpdump/... - pcap",           OPEN_INFO_MAGIC,     libpcap_open,             "pcap",     NULL, NULL },