I am looking for motherboard for headless linux server.

How well are current motherboards supporting headless mode ( server mode = no video card, no keyboard, no mouse )?

I have gone through several motherboard manual files. Their documentation about headless mode support is not clear.

From one Gigabyte manual BIOS section
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Halt on:
No Errors The system boot will not stop for any error that may be detected and you
will be prompted.
All Errors Whenever the BIOS detects a non-fatal error the system will be stopped.
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The first option No Errors would be ok but does the PC prompt for the user to press F1 or something like that? Which would mean that the boot will halt in fact.

Other motherboards ( MSI etc. ) and BIOSes had similar functions but they are not clearly documented either.

Many older motherboards dont support headless mode, they halt the booting process waiting for the user input.