I never understood what's the point of having quantifiable data in a resume for a software engineer.
Most of the time it'll likely end up being made up, as you don't have access to financial data and cannot estimate an impact your work had on a business.
Unfortunately, it's what recruiters look for and it's necessary in today's job market. There are other ways you can quantify a line that isn't financial - e.g. time saved, improved algorithm complexity, reduction of support queries, etc.
Most of the time it'll likely end up being made up, as you don't have access to financial data and cannot estimate an impact your work had on a business.