I got a request to assist a developer in adding a radio check in old symphony code. I had to add a column in postgres database which was easy because I knew the table and what column to add. Finding the code section was bit tricky because it was first time working with that code base. I started inspecting the frontend and seeing if there's any call to function in html tags, I found one and using that I searched the codebase, then realised I have to make the code aware about the column I added so I added that column in schema.xml and ran build propel command. After that I wrote some code to display warning based on radio button check.