I learnt the Model View Controller architecture employed in most Web Apps, along with common javascript libraries like JQuery and React to improve the UI of the website. I also helped update features like Single Sign On. Got hands on experience in C#.
What I wish was different
I also had to work with old code that used Visual Basic and .NET, so some projects were a bit dry.
Advice
To understand how user-centered software development works and get better at rearranging and incorporating old interfaces with modern architectures.