At the dialog called "Set format for notice" you can specify the preferred format for the output of a conversion, see also Create list. For example, you can set the format for the output to suit the needs for a text editor, a spread sheet application (csv) or a browser (html). You can set the formats for that dialog not only systemwide but also user specific.
Rules for the replacement:
$SVALUE will be replaced by the value in source.
$SUNIT will be replaced by the unit in source.
$TVALUE will be replaced by the value in target.
$TUNIT will be replaced by the unit in target.
The format in the example above produces the following output:
42 [Inch (in.,")] = 1.07 [Meter (m)]