So I asked Electrovaya if they were also supplying MTB. Here is their response. You figure it out as it is a bit cryptic.
Electrovaya provides lithium ion battery systems for Vicinity electric buses and trucks, as per the press release 10/13/2021.
We never mentioned the name of the customer in the Electrovaya Announces Commercial Launch of its Electric Bus Battery in the press release 03/17/2021