A lot of us have a lot of tabs open at once. Most browsers are now creating grouping functions to help with the chaos of the browser tab bar. The label for the browser tab is created using the HTML title tag.
For example:
<head><title>100 Days of A11y Home</title></head>
It's important when creating web pages to always have this field complete using the methodologies appropriate to the technology used. For example, in Sitefinity, the name of the page is the page title and what will show in the browser tab.
Relates to: WCAG 2.4.2 Page Titled (Level A)