It's possible the original code had a //comment and it was stripped when they created the F/OSS repository.

This is a very insightful comment. There has also been some debate about the appropriateness of non english comments and comments that only made sense in context of internal code names for Cisco projects. The high level test we used was lets get the basic code out on github as early as possible.

It's all very well when it's a simple variable but quite often I have come up against variables that would take a whole paragraph of text to explain their purpose and don't have a concise or obvious name.

I find quite often a little hard to believe. Occasionally, maybe; and why not provide a paragraph of text? Sometimes it's the right thing to do.

Then write a paragraph of text. An hour writing today will save weeks of reverse engineering later.