One of our clients internally uses an odd text file format with ~ as the field delimiter and a fixed-width based header & footer containing metadata. And still

One of our clients internally uses an odd text file format with ~ as the field delimiter and a fixed-width based header & footer containing metadata. And still sometimes send such files with names ending .csv. ~ is a better choice for field separator though, it is far less commonly used in most datasets and natural languages. | can also make sense for the same reason, and visually looks like a column divider as an extra bonus.