Backstory:
Got into a "fellowship" program with a community. They provide the templates for their website and we have to work and edit it to suit their needs. Now with a bunch of colleagues who have also been selected I finished the first part (i.e building the site) now they are training us to use their APIs and include it in their site and build the backend.

All of this I am doing without pay and according to them the benefit I get is "understanding how the industry works" and that "it will benefit us" with a promise that if we finish their sites, companies and startups will give us paid internships. I already know how APIs function and I'm not that invested in frontend stuff.

Jumping to the main question:
Should I continue here or should I quit?
Is this how the tech industry works?
Also an explanation to your answer will be great too!