Since GTK 4.10 we should use this to select a font.
However there is no screenshot on that page in the docs.
And a second question which is kind of related.
In GTK 3.x there was a font selection panel, which one could embed into the notebook, for example and make it look like font selection property among many others.
My understanding is that this interface is gone in 4.10 and so I have to use just a “font picker”, which is just a button.
Because, just like for file selection and printing, we reserve the right to use a native font selection dialog, if one exists. Currently, the font selection dialog used is the same as GtkFontChooserDialog.
Yes.
You can still use deprecated API: it’ll only matter if (and when) you decide to port your code to GTK5.