what are # +, # - comments?

[methsmonker42zero]

i jupytext converted back a jupyter notebook to py and it overwrote the file without query, so far so good.
but in the resulting file, there are # +, # - commands enclosing only some of the former cells in the jupyter notebook, so what do these mean and why do they only enclose some of the former cells, what is special about the cells enclosed by these comments?

[mwouts]

Hey @methsmonker42zero , these markers are typical of the light format documented here.

You might prefer to use the percent format instead (jupytext --to py:percent). That format is documented here, and is better supported in other IDEs like VS Code or PyCharm.