EXHIBIT 99.19

CUSIP No. 09228F103

AGREEMENT CONCERNING JOINT FILING

OF SCHEDULE 13D

The undersigned agree as follows:

(i) each of them is individually eligible to use the Schedule 13D/A to which this Exhibit is attached, and such Schedule 13D/A is filed on behalf of each of them; and

(ii) each of them is responsible for the timely filing of such Schedule 13D/A and any amendments thereto, and for the completeness and accuracy of the information concerning such person contained therein; but none of them is responsible for the completeness or accuracy of the information concerning the other person making the filing, unless such person knows or has reason to believe that such information is inaccurate.

This Agreement may be executed in any number of counterparts, each of which shall be deemed to be an original, but all of which, taken together, shall constitute one and the same instrument.

Dated: November 17, 2023

V. PREM WATSA
/s/ V. Prem Watsa
THE SECOND 810 HOLDCO LTD.
By:	/s/ V. Prem Watsa
	Name:	V. Prem Watsa
	Title:	Director
THE SECOND 1109 HOLDCO LTD.
By:	/s/ V. Prem Watsa
	Name:	V. Prem Watsa
	Title:	President
THE SIXTY TWO INVESTMENT COMPANY LIMITED
By:	/s/ V. Prem Watsa
	Name:	V. Prem Watsa
	Title:	President
12002574 CANADA INC.
By:	/s/ V. Prem Watsa
	Name:	V. Prem Watsa
	Title:	President
FFHL GROUP LTD.
By:	/s/ V. Prem Watsa
	Name:	V. Prem Watsa
	Title:	President

FAIRFAX FINANCIAL HOLDINGS LIMITED
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	President and Chief Operating Officer
FAIRFAX (US) INC.
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
ODYSSEY US HOLDINGS INC.
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
ODYSSEY GROUP HOLDINGS, INC.
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
ODYSSEY REINSURANCE COMPANY
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
HUDSON INSURANCE COMPANY
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D

CRUM & FORSTER HOLDINGS CORP.
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
UNITED STATES FIRE INSURANCE COMPANY
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
THE NORTH RIVER INSURANCE COMPANY
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
RESOLUTION GROUP REINSURANCE (BARBADOS) LIMITED
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
NORTHBRIDGE FINANCIAL CORPORATION
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
FEDERATED INSURANCE COMPANY OF CANADA
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
NORTHBRIDGE GENERAL INSURANCE CORPORATION
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D

VERASSURE INSURANCE COMPANY
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D

ZENITH INSURANCE COMPANY
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D

1102952 B.C. UNLIMITED LIABILITY COMPANY
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
ALLIED WORLD ASSURANCE COMPANY HOLDINGS, LTD
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
ALLIED WORLD ASSURANCE COMPANY HOLDINGS I, LTD
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
ALLIED WORLD ASSURANCE COMPANY, LTD
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
ALLIED WORLD ASSURANCE HOLDINGS (IRELAND) LTD
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D

ALLIED WORLD ASSURANCE HOLDINGS (U.S.) INC.
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
ALLIED WORLD INSURANCE COMPANY
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D

AW UNDERWRITERS INC.
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
ALLIED WORLD SPECIALTY INSURANCE COMPANY
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
NEWLINE HOLDINGS UK LIMITED
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
NEWLINE CORPORATE NAME LIMITED
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D

NEWLINE INSURANCE COMPANY LIMITED
By:	/s/ Peter Clarke
	Name:	Peter Clarke
	Title:	Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D

BRIT LIMITED
By:	/s/ Gavin Wilkinson
	Name:	Gavin Wilkinson
	Title:	Group Chief Financial Officer
BRIT INSURANCE HOLDINGS LIMITED
By:	/s/ Gavin Wilkinson
	Name:	Gavin Wilkinson
	Title:	Group Chief Financial Officer
BRIT UW LIMITED
By:	/s/ Gavin Wilkinson
	Name:	Gavin Wilkinson
	Title:	Group Chief Financial Officer
BRIT REINSURANCE (BERMUDA) LIMITED
By:	/s/ Gavin Wilkinson
	Name:	Gavin Wilkinson
	Title:	Group Chief Financial Officer