(See the best response by Nadrew.)
I have a particularly unreliable internet at home, and use Linux as my primary operating system. I am unwilling at this time to install Windows into a virtual machine or as a dual-boot operating system when Byond would be my only purpose for it.

My hope was to set up VSCode as a text editor (complete), work out and write a simple cross platform map editor (fortunately, byond's map data is relatively simple), and work as such, utilising the webclient's features to build the user interface entirely, and treat the Webclient as a 'first class citizen'.

My current issue is that I am unable to actually test my games. I am using the newest version of Chromium, Chrome, and Firefox, and have been unable to load up any Webclient games either on the website or locally.

At the moment, locally is all that I'm really looking for.

I start the server as follows:

DreamDaemon file.dmb -webclient

(Port is defined within byond.txt, and is connected to correctly.)

Upon navigating to localhost:port within my browser, I simply receive an 'Internal Server Error' listed, and within my browser console, 'Failed to load resource: the server responded with a status of 500 (Internal Server Error')'

Is it possible to load the Webclient and work locally? What steps am I missing to do so?

Apologies for any typos or issues, or if I'm unclear. Typing from a phone at the moment. Also apologies if this is the wrong forum section; Linux talk is particularly dead, someone from Windows may want to be able to do this same thing, and the last post in the Webclient specific thread is from over a year ago, so it seemed rude to necro it.

If this has already been covered, I also apologize. I've attempted searching several times on byond, Reddit, and even just simple googling to see if there are any solutions.
Best response
You still need to access the BYOND site to load the webclient (as it's actually handled by BYOND's site), you'd need to navigate to[port]
Ah, understood. Thank you for the solution, then.