According to the direct formulation of the question to realise the value of a property you need to use CMain::GetProperty()
$description = $APPLICATION->GetProperty("description");
However, this mechanism works on the technology of deferred functions
, this means that depending on the call may return different results.
The author suggests using the CMain::ShowProperty()
However, this possibility exists only in the template of the site and does not imply further manipulation of the result.For example, to add in description the user's city to use ShowProperty for data manipulation is absolutely impossible, you should instead subscribe to an event onEpilog of the main module and via the GetProperty + SetProperty to change the value of the string