Find the following lines in this file:
#fiper.help.language=English
fiper.help.url=https://help.3ds.com
The default value of fiper.help.language is English. The only other supported language is Japanese.
If you want, you can change it to Japanese by removing the # in the fiper.help.language line to uncomment it, and replace English by Japanese.
Note that, documentation in Japanese language is usually not available at the time of GA release. It becomes available sometime afterward.
If you want, you can replace https://help.3ds.com by the NodeJS server URL of your served documentation.
Example:
fiper.help.url=http://servername.com:4040
You can locate the actual NodeJS server port number for the documentation installation in the following file:
<documentation_install_dir>\StartDocumentationUsingJavaSearch.txt