Not Christmas.
But POTUS has ten days to act on what Congress has done. However, that ten day interval does not commence until the legislation is formally submitted to the executive.
With the porkulus bill, as of yesterday, that had not yet happened in the afternoon. I could be off by a day. But I think yesterday was the last day they (Congress) had to “get 'er done”. You see:
-
If Trump does nothing during the ten days and
-
If the Congressional term ends during that ten day interval then
The legislation dies without Trump having done anything at all.
The Congressional term ends on January 3, 2021, which is a Sunday. On that day the 116th Congress passes into history and exists no longer.
ETA
OK, here is a bit more detail from the Constitution of the United States of America:
The Presentment Clause, which is contained in Article I, Section 7, Clauses 2 and 3, provides:
Every Bill which shall have passed the House of Representatives and the Senate, shall, before it become a Law, be presented to the President of the United States: If he approve he shall sign it, but if not he shall return it, with his Objections to that House in which it shall have originated, who shall enter the Objections at large on their Journal, and proceed to reconsider it. If after such Reconsideration two thirds of that House shall agree to pass the Bill, it shall be sent, together with the Objections, to the other House, by which it shall likewise be reconsidered, and if approved by two thirds of that House, it shall become a Law. But in all such Cases the Votes of both Houses shall be determined by Yeas and Nays, and the Names of the Persons voting for and against the Bill shall be entered on the Journal of each House respectively. If any Bill shall not be returned by the President within ten Days (Sundays excepted) after it shall have been presented to him, the Same shall be a Law, in like Manner as if he had signed it, unless the Congress by their Adjournment prevent its Return, in which Case it shall not be a Law. Every Order, Resolution, or Vote to which the Concurrence of the Senate and House of Representatives may be necessary (except on a question of Adjournment) shall be presented to the President of the United States; and before the Same shall take Effect, shall be approved by him, or being disapproved by him, shall be repassed by two thirds of the Senate and House of Representatives, according to the Rules and Limitations prescribed in the Case of a Bill.
So we find there that Sundays do not count. I have not figured the days with precision. But it is safe to say we are getting very, very close. 
ETA
I’ve had yet another look. Way I read the calendar:
Even if Congress formally presented the porkulus to POTUS yesterday, he can kill it without doing a thing. This is because the Constitution carves out Sundays, which I did not realize at first. Way I see it, the ten days is up on January 4, 2021. And by then the 116th Congress will be no more.
It has been observed that Trump plays chess while others are playing checkers. He was silent and announced his objections only very belatedly. Have to wonder if Trump has been aware of this Constitutional wrinkle all along. 