Who funds Extinction Rebellion?

Paul Homewood writes:

Extinction Rebellion is no local grassroots NGO. Instead, it receives major financial support from American and UK millionaires. …

That would be referring to Rory Kennedy (daughter of former U.S. Senator Robert F. Kennedy) and Aileen Getty (a granddaughter of former U.S. oil businessman Jean Paul Getty), who started the Climate Emergency Fund which has given hundreds of thousands of dollars to Extinction Rebellion. Getty’s foundation even touts its support for Extinction Rebellion. …

Not quite grassroots, is it?