UseReducedFontsService

An alternative service that uses a reduced set of font resources, supporting a limited set of language characters, will be downloaded. Downloading the smaller set of font resources reduces the download size of a .vtpk by around 80 Mb. This omits the large Arial Unicode font, that is used to support many characters for the full world basemap. This makes this option unsuitable for some locales or when your offline vector tiled layer includes certain character sets. For example, this option will not display Chinese, Japanese, Thai, Korean or Georgian characters. You should confirm that this option is suitable for your specific use-case.

You can view a set of vector tile styles which use the reduced font services https://www.arcgis.com/home/group.html?id=c61ab1493fff4b84b53705184876c9b0. This option is not recommended for Esri basemap services that do not have an equivalent "for export" version.