It was 300kB.

>  If we had 300 kilobyte blocks starting today, it's 1x the peak sync time in 2019, and we get back to the 2013 sync time in 2035.

https://diyhpl.us/wiki/transcripts/magicalcryptoconference/2019/why-block-sizes-should-not-be-too-big/

Filiprogrammer

I think that once upon a more peaceful time, Luke was arguing 200kB soft-blocklimit (like it used to be 750kB) which was a meaningful thing to propose (though I wouldn't have gone for it personally)