Gmail

Background
Gmail is an email service provided by Google. It provides a webmail interface, accessible through a web browser, and is also accessible through the official mobile application.

When the service launched on April 1, 2004, Gmail originally provided a storage capacity of one gigabyte per user, which was significantly higher than its competitors offered at the time. Today, the service comes with fifteen gigabytes of storage for free, which is divided among other Google services, such as Google Drive and Google Photos. As of 2019, it has 1.9 billion active users worldwide, making it the largest email service in the world.

1st (known) Screen (2010s-2020)
Visuals: On a white (if the device is on light mode) or gray (if the device is on dark mode) background, we see an envelope with a wide "M" over it. The Google logo in is present at the bottom.

Technique: None.

Audio: None.

Availability: Can be seen when you start an old version of the Gmail app on a tablet or phone.

2nd (known) Screen (2020-)
Visuals: On a white (if the device is on light mode) or gray (if the device is on dark mode) background, we see a stylized "M" colored blue, maroon,, yellow and in different sections. "Google Workspace" is below.

Technique: None.

Audio: None.

Availability: Can be seen when you start the Gmail app on a tablet or phone.