EXHIBIT 2.3

CUSIP No.  Y0436Q109

AGREEMENT CONCERNING JOINT FILING
OF SCHEDULE 13D

The undersigned agree as follows:

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

(ii) each of them is responsible for the timely filing of such Schedule 13D 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:  March 9, 2020

1

V. PREM WATSA
/s/ V. Prem Watsa
V. Prem Watsa
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
THE SIXTY THREE FOUNDATION
By:	/s/ V. Prem Watsa
	Name: V. Prem Watsa
	Title: Director

2

FAIRFAX FINANCIAL HOLDINGS LIMITED
By:	/s/ Peter Clarke
	Name: Peter Clarke
	Title: Vice President and Chief Operating Officer
FFHL GROUP LTD.
By:	/s/ V. Prem Watsa
	Name: V. Prem Watsa
	Title: President
FAIRFAX (BARBADOS) INTERNATIONAL CORP.
By:	/s/ Peter Clarke
	Name: Peter Clarke
	Title:  Attorney-in-Fact pursuant to Power of
	Attorney attached to this Schedule 13D
WENTWORTH INSURANCE COMPANY LTD.
By:	/s/ Peter Clarke
	Name: Peter Clarke
	Title:  Attorney-in-Fact pursuant to Power of
	Attorney attached to this Schedule 13D

3

TIG INSURANCE (BARBADOS) LIMITED
By:	/s/ Peter Clarke
	Name: Peter Clarke
	Title: Attorney-in-Fact pursuant to Power of
	Attorney attached to this Schedule 13D
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

4

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
GREYSTONE 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

5

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

6

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

7

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

8

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
ALLIED WORLD SURPLUS LINES INSURANCE 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, AG
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 (EUROPE) DAC
By:	/s/ Peter Clarke
	Name: Peter Clarke
	Title: Attorney-in-Fact pursuant to Power of
	Attorney attached to this Schedule 13D

9

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

10

ZENITH INSURANCE COMPANY
By:	/s/ Peter Clarke
	Name: Peter Clarke
	Title: Attorney-in-Fact pursuant to Power of
	Attorney attached to this Schedule 13D
RIVERSTONE HOLDINGS LIMITED
By:	/s/ Nicholas C. Bentley
	Name: Nicholas C. Bentley
	Title: Chairman of the Board and Chief Executive Officer
RIVERSTONE INSURANCE (UK) LIMITED
By:	/s/ Nicholas C. Bentley
	Name: Nicholas C. Bentley
	Title: Director
RIVERSTONE CORPORATE CAPITAL LIMITED
By:	/s/ Nicholas C. Bentley
	Name: Nicholas C. Bentley
	Title: Chairman of the Board

11

BRIT LIMITED
By:	/s/ Mark Allan
	Name: Mark Allan
	Title: Chief Financial Officer and Director
BRIT INSURANCE HOLDINGS LIMITED
By:	/s/ Mark Allan
	Name: Mark Allan
	Title: Director
BRIT REINSURANCE (BERMUDA) LIMITED
By:	/s/ Mark Allan
	Name: Mark Allan
	Title: Director
BRIT SYNDICATES LIMITED
By:	/s/ Mark Allan
	Name: Mark Allan
	Title: Director
BRIT UW LIMITED
By:	/s/ Mark Allan
	Name: Mark Allan
	Title: Director

12

TIG INSURANCE COMPANY
By:	/s/ Peter Clarke
	Name: Peter Clarke
	Title: Attorney-in-Fact pursuant to Power of
	Attorney attached to this Schedule 13D
ADVENT CAPITAL (HOLDINGS) LTD
By:	/s/ Peter Clarke
	Name: Peter Clarke
	Title:  Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
ADVENT CAPITAL (NO. 3) LIMITED
By:	/s/ Peter Clarke
	Name: Peter Clarke
	Title:  Attorney-in-Fact pursuant to Power of Attorney attached to this Schedule 13D
THE SECOND 810 HOLDCO LTD.
By:	/s/ V. Prem Watsa
	Name: V. Prem Watsa
	Title:  Director

13