This is a spin-off from this question: How to view Salesforce1 on the desktop? (reloaded)
It was answered and several workaround did exist. But the accessibility of the Salesforce Mobile App degraded over time and basically all proposed solutions seem not to work anymore. In detail the proposed solution are only showing Salesforce Classic (aloha) but not the mobile App and not LEX.
But still the requirement to see and debug the Salesforce Mobile App is HUGE!
We have several Lightning Components and Visualforce Pages which needs distinct logic, rendering, layout and functionality for the Mobile App. Debugging it on the phone with Developer Tools is a real pain in the ass.
So we hope to find new workaround or even an official solution to make the life of us devs and tester a bit easier.