The line wasn't written in 2014, that's just the earliest that the history goes back. Presumably it's no newer than the early 2000s.

Considering that initial commit contains 400k lines, I would say there is a very long history before git was used.

The comment in the code slightly above says:

    this doesn't work in perl 5.6.2! grrrr

So this code is at least 20 years old, and probably pre-2000.

https://exiftool.org/ancient_history.html

    Sept. 26, 2008 - Version 7.44
           - Added read support for DjVu images

There were probably enough systems running perl 5.6.2 around 2008 to cause bug reports, or the code was migrated from an older piece of code and added to ExifTool.

It was not uncommon to manually ./configure, make, make install tarballs locally in those days, especially not on systems like Slackware so I can see it being possible to have old packages installed that were not automagically updated.

I remember before 2007 seeing people using eval and thinking "what on earth is wrong with you?"

I'd accept this for maybe pre-2000, but people should really know better.