How to customize icons and link

[lucamauri]

In the top navigation bar of the QuickStatements main page there are two icons:

• a 🌍 emoji that links to https://tooltranslate.toolforge.org/#tool=24
• the icon 32px-Toolforge_logo.svg.png from Commons that links to https://quickstatements.toolforge.org/

I would like to customize the two icons and their links, but analyzing the code, I can't find where and how they are defined.

Can someone please explain how they are injected in the page?