It appears to be the True Patriot Love Foundation. I have e-mailed them.

After a couple e-mails to the True Patriot Love Foundation that generated no response (except that they put me on their mailing lists), I connected with the Managing Director via LinkedIn. After two messages to her, I have received a response: "The local fundraising committee requested that we hold off unveiling the plaque until their unveiling ceremony and we are respecting their wishes." I don't know who the 'local fundraising commitee' is, and why this plaque would continue to be covered months after the other plaques in Scarborough have been unveiled. If neither the True Patriot Love Foundation nor the 'local fundraising committee' cares about uncovering this plaque to honour Canada's fallen soldiers, I give up. I am closing this issue.