In the Attributes section of an application, you can set the app's icon. You can also add a link - this is placed to the right of the subtitle text:
How can I add a link to the icon itself, so that clicking on the three coloured blocks navigates somewhere?
The icon seems to be loaded dynamically, into this div:
<div class="header-section jimu-float-leading" data-dojo-attach-point="headerNode">
<img class="logo jimu-float-leading jimu-leading-margin1" data-dojo-attach-point="logoNode" src="images\logo.png" style="height: 30px; min-width: 30px; margin-top: 5px; cursor: default;">
Which script builds this section of the UI? It should be possible to wrap the whole thing in an <a href> tag.