src/Doc/isar.sty

 
 \newcommand{\indexdef}[3]%
 {\ifthenelse{\equal{}{#1}}{\index{#3 (#2)|bold}}{\index{#3 (#1\ #2)|bold}}}
 \newcommand{\indexref}[3]{\ifthenelse{\equal{}{#1}}{\index{#3 (#2)}}{\index{#3 (#1\ #2)}}}
 
-\newcommand{\isatt}[1]{{\def\isacharminus{-}\def\isacharunderscore{\_}\tt #1}}
+\newcommand{\isasystem}[1]{{\def\isacharminus{-}\def\isacharunderscore{\_}\tt #1}}
 \newcommand{\isatool}[1]{{\def\isacharminus{-}\def\isacharunderscore{\_}\tt isabelle #1}}
 
 \newcommand{\indexoutertoken}[1]{\indexdef{}{syntax}{#1}}
 \newcommand{\indexouternonterm}[1]{\indexdef{}{syntax}{#1}}
 \newcommand{\indexisarelem}[1]{\indexdef{}{element}{#1}}