Hello everyone,
I’m trying to do something seemingly simple, but I can’t find the right file, seems like. As it’s all a bit new to me, please excuse some unclear/inaccurate wording.
Problem:
I want to change the title of the JupyterLab page, to see my custom name in the browser tab. It’s that simple 
The reason for that is that there are two clusters users can log into, and I want the users to know when they are at a given moment, at a glance. So I want the JupyterLab page title to be “JupyterLab - A” on one cluster, and “JupyterLab - B” on the other one. This way you just look at the browser tab and know where you are.
Context:
JupyterLab is spawned by SLURM/JupyterHub, it’s an AWS cluster, users can choose to stay on the login node, or use the compute node(s). Both clusters are configured in the same way.
What I tried so far:
All I need to change is the “title” tag. As I couldn’t find straight answers online, I started searching for the actual files, and found usr/local/share/jupyter/lab/index.html first. But of course that’s not it: when I modify it on the login node, and on the compute node, I see my customized title when it’s being spawned, but then the standard, default page is loaded, with “JupyterLab” title.
Searched some more, and found the …/jupyterlab_server/templates/index.html, which has what looks like a Jinja template, with the title block. I tried to add some text there to see if that is the file being used, but no luck.
So here’s the question: where exactly are the template files (or html files in general) that are being used when JupyterLab is launched, and is there a way to customize this for all users from the central server (i.e. without having to modify this in each user’s local installation)? Does it require generating some config file, like what JupyterHub has?
I understand that the actual JupyterLab is started with some JavaScript process, and the page I’m looking at when I work on a computer using the cluster is somewhere on my local machine. But there is somewhere - I suppose - a template and a configuration file, that could be modified… But I’m really puzzled about where to find them!
Thank you in advance for any guidance