As a white guy, it absolutely might not be my place to suggest some useful things we white folks should be doing on Juneteenth.
That said, getting to know & financially supporting the work of Critical Resistance seems like a mighty good place to start (in addition to responding to whatever mutual aid requests from Black folks you can do on here).
If you want to go more introspective, you might also look at some of the Catalyst Project's resources: https://collectiveliberation.org
Basically, it seems like a particularly good day to act on the fact that "nobody's free until everybody’s free" in the words of Fannie Lou Hamer.
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