Sure! It’s here
In the ‘Balance Adjustments’ section.
At the moment - Belladonna’s “Dispel Buff” immunity only prevents heroes like Melandor, Seshat, Sonya etc debuffing any buffs. i.e. it prevents them from removing any buffs, such as Attack up or taunt.
Heroes like Diochan, Ithar and The Hatter have skills which ‘steal’ buffs - so they don’t ‘remove’ the buff, they take it and place it on someone on their own team.
This change means that won’t work anymore.
This makes it more inline with what you’d expect from a ‘undispellable’ buff - but in practice this means that it nullifies the above heroes as counters so if coming up against a Belladonna/BK combination (for example) you’re going to have to either replace the buffs (e.g. attack up can be overwritten with attack down) - or just kill the hero.