Each font file of San Francisco font family contains a table with SF Symbols metadata. This data is completely identical for the same version of the font, across all the individual font files.
SF Symbols app includes a font resource named SFSymbolsFallback.ttf with a unique font version.
Here's a list of resources we've seen so far:
| Font version | Font date | Notes |
|---|---|---|
| 15.0d5e5 | 2019-07-10 | Distributed during macOS Catalina beta |
| 15.0d7e10 | 2019-08-09 | SF Symbols app v.1.0 (13) |
| 15.0d7e11 | 2019-08-14 | Distributed during macOS Catalina |