As far as I understand GAAP reporting standards actually require them to report gains on those positions as "earnings". But they do report non-GAAP earnings sometimes excluding them. E.g. Google earnings per share last quater is $9.11 GAAP vs $2.85 non-GAAP (mainly because of SpaceX shares).

Useful piece on this from Owen Lamont:

https://www.acadian-asset.com/investment-insights/owenomics/...

A recent Zitron claim is that they’re booking unrealized gains tied to these private labs. Google’s net revenues being a recent example.

It's not a "Zitron claim". it's literally in the filings...