avrdude fuse error when programming ATMEGA328 without crystal
The ATMega328P datasheet has the following table in it:

The top 5 bits of the of the Extended Fuse Byte are default 1 and are reserved.  You're not really supposed to change them, since they might be used in the future for a 328P-like part and setting them to something other than 1 could have unexpected results.  In the 328PB variant bit number 3 is used for &quot;Disable Clock Failure Detection&quot;.
The lower three bits of 0xFD and 0x05 are both 0b101.  In other words, taking into account only the bits you should be setting, for the BODLEVELn fuses, they would have the same effect.  But you are being WARNED that you should be using 0xFD rather than 0x05 for the above reason.
The boards.txt that comes in the breadboard-1-6-x.zip has a line that looks like this:

atmega328bb.bootloader.extended_fuses=0x05

You could change this yourself by editing the file, but really for what you're doing I'd recommend MCUdude MiniCore which is comparatively up to date.  If nothing else, its boards.txt file has been written with the correct fuse values.  You can see there for a plain 328P (not PB) which does not support clock failure detection, the CFD bit is just hardcoded to 1 in the file.
The message you're seeing is a &quot;WARNING&quot; through, rather than &quot;ERROR&quot;.  The distinction being that warnings don't actually stop you from continuing.  It is likely that if you're having a problem isn't not really because they've incorrectly specified the high-order bits of the fuse.  If it's halting, it may be arduino-builder see a non-zero exit code for avrdude and thinking this means &quot;ERROR&quot; rather than &quot;WARNING&quot;, in which case this problem will go away if you edit the boards.txt file (or adopt MiniCore) such that no longer produces the warning.
Unless you've brought the effective system clock below 1MHz, probably lower still, it's not likely that you'll need to change from the default ISP clock rate.  If you do though, that can also be done by editing board package files.