According the article, Corbyn and Labour are determined to stop Brexit. The article states that Johnson doesn’t have the votes to pass it. Britain’s convoluted structure and multiple political parties makes this very difficult. I’ll believe it when I see it.
And even then, I wouldn’t put it passed the Left in that country to someday attempt to rejoin the EU.
If they don’t agree, the UK goes to hard-Brexit and they have to call new elections. Johnson will tell the courts to screw off if they try to stop the UK from leaving without a deal. This is the best deal they are going to get. The Good Friday agreement ties their hands so Northern Ireland has to stay in the EU as long has Ireland does.