My guess, from looking at the pin list and the module’s internal schematic, is that OUT_MOD is the actual RF output, and that OUT_ANT is actually the input to the internal antenna. In the dev board schematics, they have the ability to cut the trace between those pads, and instead jumper them together to an SMA jack for “RF testing”.
It’s hard to be sure since their module’s internal schematic is incomplete.
Not that this question has any relevance to you: you bridge those pads like they tell you to and call it a day.
SWDCLK and SWDIO are the Serial Wire Debug interface, the clock and IO lines, respectively. Just like the datasheet says. What’s stopping you from googling to find out what SWD is?