ref: dfc2c1723bbba30725202ffb9139d74402ebfd91
dir: /sys/src/cmd/python/Doc/texinputs/python.ist/
line_max 100
headings_flag 1
heading_prefix " \\bigletter "
preamble "\\begin{theindex}
\\def\\bigletter#1{{\\Large\\sffamily#1}\\nopagebreak\\vspace{1mm}}
"
symhead_positive "{Symbols}"
numhead_positive "{Numbers}"