How to configure browser used by web page Reminders? How can I change which browser the Mac Reminders.app uses to open "this webpage" associations for a Reminder, so I can change the "Open Google Chrome Canary" notification button to an "Open Mozilla Firefox" button?

Given I've created a Reminder for a Webpage on my phone by asking Siri to "remind me about this tomorrow", when the Reminder appears on my laptop running the latest public build of OS X, then I expect the Open button to offer to open it in my default browser, or just not mention the browser and behave as open(1) does.

Instead, what I see is "Open in Google Chrome Canary":



This has me flummoxed: I open that browser like once a year, and my default browser is Mozilla Firefox. I've no clue why Reminders has latched onto it as The Chosen Browser for webpage reminders.

ETA: I have deleted Google Chrome Canary. After relaunching Reminders.app, webpage reminders show, instead of its icon, the "invalid app" default icon with slashed-circle. Clicking that button does nothing. No console logs appear.
My results from user edgarator’s solution: Successful for macOS Safari users

Summary


Chrome icon changed to Safari after CleanMyMac Chrome Uninstall
Chrome icon appears again after Chrome is reinstalled
Removing files individually still had the Chrome icon, resulting in “no effect”
Firefox will open Reminders URL’s if it is set as the default web browser.
Firefox can’t share websites to Reminders. 
Firefox can’t use Siri to send websites to Reminders. 


Software Versions


macOS Sierra:         10.12.6
Apple Reminders:      4.0 (441.11)
CleanMyMac:           1.10.4
Google Chrome:        61.0.3163.79 (Official Build) (64-bit)
Safari:               10.1.2 (12603.3.8)
Firefox:              55.0.3 (64-bit)


My Process

Safari’s has a share website to Reminders feature (Share-to-Reminders).  Details can be added to a website reminder that is being sent to Reminders without leaving the browser.  

Now the problem: The shared links in Reminders uses Chrome icons which open Reminders items in Chrome, instead of Safari—or a designated browser.

I used CleanMyMac to uninstall Google Chrome, it's folders, and files.

After uninstalling Chrome, it's icon was replaced by Safari’s icon, pressing on the icon opened the link in Safari.

I then changed the default web browser to Firefox.  

Clicking on the URL’s directly, or Control-clicking the URL’s in the Info Pane, opens the link in Firefox (default browser).  

However, Firefox does not support Share-to-Reminders, so websites can’t be shared to Reminders from Firefox.  This also means that Siri does not execute the Share-to-Reminders command while using Firefox.