I just tried the
Manjaro-Arm-Minimal-rpi-18.05.07-2045.img from the share on my RPi3B.
I got it to boot and display the console on a TV without a hitch. I could not do much because I could not sudo and did not know the root password. I now read the other post and I know.
My initial attempt was to boot with a UART-to-USB adapter connected to the GPIO ports (14-15) but I did not get any output.
I read this post on raspberry.org that suggest adding
enable_uart=1 at the bottom of config.txt but that had the result of causing a kernel panic (“bad PC value”).
What do I need to do to enable console output on GPIO? I assumed that it was enabled by default.