This list complete as of version 14.
None of these are necessarily supported in future.

Add one to any debug value to trigger writing benchmark values to
the file "bench". This gets stripped at startup; so all values
used for other purposes are even.

Example: "fractint debug=8088" forces Fractint to think you have an
8088/8086 CPU and ignore all of the tricky 186/286/386-specific stuff.
"Fractint 8089" does the same thing, but also turns on the benchmark
timer.

16video.asmpretend not a vga
22lorenz.cforce float for 3D perspective
50fractint.ccompare estored files
70fractint.cset fpu = 0
72fractint.cdon't use fast >= 287 fpu routines
90fractals.cforce "C" mandel & julia code (no calcmand or calmanfp)
90fractals.cforce generic code for fn+fn etc types
100calcmand.asmforce use of 'code32bit' logic
200fractint.ctime encoder
420diskvid.cdon't use extended/expanded mem (force disk)
420realdos.c same for screen save (force disk)
420editpal.c same for screen save (force disk)
420jiim.c same for screen save (force disk)
422diskvid.cdon't use expanded mem (force extended or disk)
422realdos.c same for screen save (force extended or disk)
450fractint.cabort in batch mode if savename exists
470calcfract.cdisable prevention of color 0 for BTM
600printer.cpaintjet, no form feed
602printer.cpaintjet, flip image
7nn miscovl.cset getprec() digits variable to nn
870fractint.cset fpu to max 87
1010fractals.cforce fp for newton & newtbasin (no mpc math)
1234fractint.cforce larger integer arithmetic bitshift value
2222line3d.cshow amount of extra seg memory used
2224line3d.cold just-the-dots logic, probably a temporary thing
2870fractint.cset fpu to max 287 iit off
2872fractint.cset fpu to max 287 iit on
3000general.asm'~' goes to color play mode
3002realdos.cdon't show development in heading
3870fractint.cset fpu to max 387 iit off
3872fractint.cset fpu to max 387 iit on
4000miscres.cturn on math error message (off otherwise)
8088general.asmset cpu = 86, ie dont use 32 bit stuff
8088fractint.cset cpu = 86, (case in general.asm is redundant?)
9002-9100 fractint.creduce video_type to (debug-9000)/2 if init was higher
10000fractint.cdisplay cpu, fpu, and free memory at startup
10000fractint.c? (try extra hard for minimal startup memory?)

nonzero value, line3d.c, show "normal vector" errors instead of just fixing
nonzero value, prompts.c, show info if fullscreen_prompt2 array invalid