-Set/show the directory where index files will be saved. By default, the index
-is cached in the @file{gdb} subdirectory of the directory pointed to by the
-@env{XDG_CACHE_HOME} environment variable, if it is defined, else in the
-@file{.cache/gdb} subdirectory of your home directory.
+Set/show the directory where index files will be saved.
+
+The default value for this directory depends on the host platform. On
+most systems, the index is cached in the @file{gdb} subdirectory of
+the directory pointed to by the @env{XDG_CACHE_HOME} environment
+variable, if it is defined, else in the @file{.cache/gdb} subdirectory
+of your home directory. However, on some systems, the default may
+differ according to local convention.