system: You are a contract-analysis assistant performing a span-extraction task. You are given an excerpt from a commercial contract and the name of a clause type to locate within it.

Return the exact text of the requested clause, copied verbatim from the excerpt — identical wording and punctuation, with no paraphrasing, summarising, explanation, or added commentary.

The excerpt is one window of a much longer contract and often will not contain the requested clause. If the requested clause does not appear in this excerpt, respond with exactly: Not found.

Output only the extracted clause text, or the exact string `Not found.` — nothing else.

user: Contract excerpt:
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EXHIBIT D JOINT FILING AGREEMENT MFA FINANCIAL, INC. In accordance with Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended, the undersigned hereby confirm the agreement by and among them to the joint filing on behalf of them of the Statement on Schedule 13D and any and all further amendments thereto, with respect to the securities of the above referenced issuer, and that this Agreement be included as an Exhibit to such filing. This Agreement may be executed in any number of counterparts each of which shall be deemed to be an original and all of which together shall be deemed to constitute one and the same Agreement. IN WITNESS WHEREOF, the undersigned hereby execute this Agreement as of July 6, 2020. ATHENE ANNUITY AND LIFE COMPANY By: Apollo Insurance Solutions Group LP, its investment adviser By: AISG GP Ltd., its general partner By: /s/ Matthew S. O'Mara Matthew S. O'Mara Authorized Signatory ATHENE ANNUITY & LIFE ASSURANCE COMPANY By: Apollo Insurance Solutions Group LP, its investment adviser By: AISG GP Ltd., its general partner By: /s/ Matthew S. O'Mara Matthew S. O'Mara Authorized Signatory ATHENE USA CORPORATION By: Apollo Insurance Solutions Group LP, its investment adviser By: AISG GP Ltd., its general partner By: /s/ Matthew S. O'Mara Matthew S. O'Mara Authorized Signatory ATHENE LIFE RE LTD. By: Apollo Insurance Solutions Group LP, its investment adviser By: AISG GP Ltd., its general partner By: /s/ Matthew S. O'Mara Matthew S. O'Mara Authorized Signatory ATHENE HOLDING LTD. By: Apollo Insurance Solutions Group LP, its investment adviser By: AISG GP Ltd., its general partner By: /s/ Matthew S. O'Mara Matthew S. O'Mara Authorized Signatory APOLLO INSURANCE SOLUTIONS GROUP LP By: AISG GP Ltd., its general partner By: /s/ Matthew S. O'Mara Matthew S. O'Mara Authorized Signatory AISG GP LTD. By: /s/ Matthew S. O'Mara Matthew S. O'Mara Authorized Signatory APOLLO LIFE ASSET, L.P. By: Apollo Life Asset GP, LLC, its general partner By: /s/ William B. Kuesel William B. Kuesel Vice President APOLLO LIFE ASSET GP, LLC By: /s/ William B. Kuesel William B. Kuesel Vice President APOLLO CAPITAL MANAGEMENT, L.P. By: Apollo Capital Management GP, LLC, its general partner By: /s/ William B. Kuesel William B. Kuesel Vice President APOLLO CAPITAL MANAGEMENT GP, LLC By: /s/ William B. Kuesel William B. Kuesel Vice President APOLLO MANAGEMENT HOLDINGS, L.P. By: Apollo Management Holdings GP, LLC, its general partner By: /s/ William B. Kuesel William B. Kuesel Vice President APOLLO MANAGEMENT HOLDINGS GP, LLC By: /s/ William B. Kuesel William B. Kuesel Vice President OMAHA EQUITY AGGREGATOR, L.P. By: AP Omaha Advisors, LLC, its general partner By: Apollo Hybrid Value Advisors, L.P., its sole member By: Apollo Hybrid Value Capital Management, LLC, its general partner By: /s/ Joseph D. Glatt Joseph D. Glatt Vice President AP OMAHA ADVISORS, LLC By: Apollo Hybrid Value Advisors, L.P., its sole member By: Apollo Hybrid Value Capital Management, LLC, its general partner By: /s/ Joseph D. Glatt Joseph D. Glatt Vice President APOLLO HYBRID VALUE ADVISORS, L.P. By: Apollo Hybrid Value Capital Management, LLC, its general partner By: /s/ Joseph D. Glatt Joseph D. Glatt Vice President APOLLO HYBRID VALUE CAPITAL MANAGEMENT, LLC By: /s/ Joseph D. Glatt Joseph D. Glatt Vice President APH HOLDINGS, L.P. By: Apollo Principal Holdings III GP, Ltd., its general partner By: /s/ William B. Kuesel William B. Kuesel Vice President APOLLO PRINCIPAL HOLDINGS III GP, LTD. By: /s/ William B. Kuesel William B. Kuesel Vice President
"""

Extract the exact clause related to "Source Code Escrow" from the excerpt above.