How to modify the global email template in Moodle 4.5 (e.g., "Download the mobile app" footer)?

Question

I'm working with Moodle 4.5 and trying to customize the global email template used for notifications. Specifically, I want to remove or modify the default message that appears in all emails:

"Czytasz to w e-mailu? Pobierz aplikację mobilną i otrzymuj powiadomienia na swoim mobilnym urządzeniu."

I suspect this is part of a higher-level template that wraps the content for specific emails (e.g., course notifications or enrollment emails). However, I haven’t been able to locate where this global template is managed.

Here's what I’ve tried so far:

Language customization: I navigated to Site administration > Language > Language customisation and found many strings related to email content. While I was able to modify some of the text, the mobile app link and message still appear.

Site administration > Messaging settings: I reviewed the messaging settings but didn’t find an option to adjust the email layout or this particular string.

Documentation and forums: I searched the Moodle documentation but couldn’t find clear instructions on editing the overarching email template.

Does Moodle have a global email template that wraps the content of all messages? If so, where can I find it, and how can I customize it? Do I need to edit a specific PHP or HTML file in Moodle's core, or is there a plugin or admin setting for this?

Any help or guidance would be greatly appreciated!