> Markdown is not a specification
Not by that name... https://commonmark.org/
Not by that name... https://commonmark.org/
If you are in restructuredText world there is one specification and all implementation adhere to it, be it pandoc, sphinx, pelican, nikola. The beauty of it is that it has extension mechanisms which provides enough room for each tool to develop it. But markup can be parsed by any tool.
[1] https://docutils.sourceforge.io/docs/ref/rst/restructuredtex...
It's better than "designed by a committee" standards, but it lacks elegance or maybe craftsmanship.
You don't really get bit by its lack of a standard and extensibility until after you've bought in.
It's essentially designed by the opposite of a committee -- rather than including everything but the kitchen-sink, it contains support for almost no usecases except the one. Which is very appealing, when you only have the one usecase.
So markdown needs to thank the popularity of Wikipedia for its success, as rst did not have any application like Wikipedia. But still rst is used widely enough with its killer Sphinx, readthedocs and now its kind of de-facto documentation writing markup in Python and many open source software world.