What is postxml and postcss?

Choose a web designer on freelancing, one written such information:
Use the HTML postxml
In postcss CSS (with flexbox)

In the search I read, that these tools themselves are not the most powerful, they work well with plugins. So I want to ask - it is good that the coder uses such methods?
July 4th 19 at 22:48
2 answers
July 4th 19 at 22:50
Well anything that helps accelerate or avoid routine
Well, when your instrument use a couple more people. Preferably -- a couple of million
In the layout there are no such tools, which could not have been used to study the day-hour-minute
July 4th 19 at 22:52
What is the difference in General? The main thing to the time honored and had a good reputation.

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