thank you for reaching out to us. I assume you are talking about the Python documentation and have edited the thread tags for you.
This is probably a copy and paste error, as the C++ documentation is more verbose when documenting this method. Or the author argued that the short description 'Sets the border type of the current group, and displays the title in the border if possible.' is technically true for both methods, it is just that it is never possible when the method is
GroupBorderNoTitle. However, I have updated the Python docs which will be reflected in the next documentation release.
As a small warning: Most of the dialog border flags are meaningless at the moment and will result in the same output. With S26 the GUI was overhauled and with that many border flags have become meaningless. I have then asked the UX and GUI development teams to update these flags, which unfortunately never happened. I must dig down on that topic again, because the current state is quite misleading. There is only one border style to be set at the moment and it will stay that way AFAIK. Will have to confirm the details with UX & GUI teams.