If you had an issue with SetHelpViewer("browser"), you will have to specify what browser specifically you want to use (Linux users especially). So for example if you have firefox installed and want to use that the command will be SetHelpViewer("firefox");.
All browser names should not be capitalised. (If you're unsure, check the help page for SetHelpViewer, it gives you nearly all options, but does not mention that there is no default browser for Linux).
From the Framapad at PGTC 2018 Tutorial:
If you had an issue with
SetHelpViewer("browser"), you will have to specify what browser specifically you want to use (Linux users especially). So for example if you have firefox installed and want to use that the command will beSetHelpViewer("firefox");.All browser names should not be capitalised. (If you're unsure, check the help page for
SetHelpViewer, it gives you nearly all options, but does not mention that there is no default browser for Linux).