As someone who wrote an XML config file for a project way back when, I can provide a few answers. For me, it was either use an off the shelf parser or write my

As someone who wrote an XML config file for a project way back when, I can provide a few answers. For me, it was either use an off the shelf parser or write my own. The config files at the time were all like apache's config - various combinations of weird syntax. XML came with parsers off the shelf and gave you some validation up front. If there were other tools at the time available, I probably hadn't found them, and XML had a lot of buzz so it was easy to find. These days all the libraries have parsers for a variety of easy to use data formats, from JSON and YAML to Protobufs and ini files.