Clarified how to use the two magical strings for cacheDir. A full exp…

…lanation

is coming in the Wiki.

README.md

@@ -116,16 +116,26 @@ Check out these prebuilt installers for a more complex demo application
 
 ## Specify cache directory
 
-By default, the artifacts are downloaded to the current working directory. This is usually fine for native installers, but if you distribute
-your application via just the launcher jar, you might want to specify where the downloaded artifacts land. See the 
-[cache dir documentation](https://github.com/edvin/fxlauncher/wiki/Optional-Cache-Directory) for more information.
+By default, the artifacts are downloaded to the current working directory. This is usually fine for per-user native 
+installers, but if you distribute your application via a system-wide native installer, or just the launcher 
+jar, you might want to specify where the downloaded artifacts land. See the 
+[cache dir documentation] for more information.
+
+[cache dir documentation]: https://github.com/edvin/fxlauncher/wiki/Optional-Cache-Directory
 
 ## Installation location
 
-It's worth noting that the two package alternatives for Windows, (EXE and MSI) have different install location defaults.
-While EXE will default to %APPDATALOCAL%, the MSI installer will default to %ProgramFiles%. If you use the MSI installer you
-might therefore need to specify the cache dir parameter as `cacheDir 'USERLIB/MyApp'` to make sure that the launcher has
-write access to download the artifacts for your application.
+It's worth noting that the two package alternatives for Windows, (EXE and MSI) have different default install locations.
+While EXE will default to [`%AppDataLocal%`], the MSI installer will default to `%ProgramFiles%`.  To write to 
+`%ProgramFiles%` one definitely does need admin privileges—that poses a problem for FXLauncher which, by default, 
+downloads updates to where it was installed. 
+
+If you use the MSI installer you will therefore need to tell FXLauncher to cache artifacts somewhere it is allowed
+to put them. For an OS-independent answer to this problem, look no further than the 
+[two magical strings][cache dir documentation], `USERLIB` and `ALLUSERS`. 
+
+
+[`%AppDataLocal%`]: https://www.howtogeek.com/318177/what-is-the-appdata-folder-in-windows/
 
 Read more about Java Packager in the official documentation: