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  <xs:element id="mgni_DebtInstrumentCappedCallConversionPrice" abstract="false" name="DebtInstrumentCappedCallConversionPrice" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:perShareItemType"/>
  <xs:element id="mgni_DebtInstrumentRepurchasedDuringPeriodFaceAmount" abstract="false" name="DebtInstrumentRepurchasedDuringPeriodFaceAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtIssuanceCostsAbstract" abstract="true" name="AmortizationOfDebtIssuanceCostsAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="mgni_AmortizationOfDebtIssuanceCostsRemainderOfFiscalYear" abstract="false" name="AmortizationOfDebtIssuanceCostsRemainderOfFiscalYear" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtIssuanceCostsYearOne" abstract="false" name="AmortizationOfDebtIssuanceCostsYearOne" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_CreditAgreement2021Member" abstract="true" name="CreditAgreement2021Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_CreditAgreement2024DebtRepricingMember" abstract="true" name="CreditAgreement2024DebtRepricingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_AlternateBaseRateMember" abstract="true" name="AlternateBaseRateMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="mgni_ExistingLendersMember" abstract="true" name="ExistingLendersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_NewLendersMember" abstract="true" name="NewLendersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_DebtIssuanceCostsAxis" abstract="true" name="DebtIssuanceCostsAxis" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:dimensionItem" type="xbrli:stringItemType"/>
  <xs:element id="mgni_DebtIssuanceCostsDomain" abstract="true" name="DebtIssuanceCostsDomain" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="mgni_DebtDiscountMember" abstract="true" name="DebtDiscountMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="mgni_DeferredFinancingCostsMember" abstract="true" name="DeferredFinancingCostsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:domainItemType"/>
  <xs:element id="mgni_DebtRefinanceCostMember" abstract="true" name="DebtRefinanceCostMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_LineOfCreditFacilityCovenantComplianceDebtUtilizationTriggeringLeverageRatioCompliancePercentage" abstract="false" name="LineOfCreditFacilityCovenantComplianceDebtUtilizationTriggeringLeverageRatioCompliancePercentage" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="mgni_LineOfCreditFacilityCovenantComplianceLeverageRatioMaximum" abstract="false" name="LineOfCreditFacilityCovenantComplianceLeverageRatioMaximum" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="mgni_DebtInstrumentPeriodicPaymentPercentageOfPrincipal" abstract="false" name="DebtInstrumentPeriodicPaymentPercentageOfPrincipal" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="mgni_DebtInstrumentAnnualPrincipalPaymentPercentage" abstract="false" name="DebtInstrumentAnnualPrincipalPaymentPercentage" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types1:percentItemType"/>
  <xs:element id="mgni_DebtInstrumentNoncashOrPartNoncashFinancingActivity" abstract="false" name="DebtInstrumentNoncashOrPartNoncashFinancingActivity" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtDiscountsAbstract" abstract="true" name="AmortizationOfDebtDiscountsAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="mgni_AmortizationOfDebtDiscountPremiumRemainderOfFiscalYear" abstract="false" name="AmortizationOfDebtDiscountPremiumRemainderOfFiscalYear" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtDiscountPremiumYearOne" abstract="false" name="AmortizationOfDebtDiscountPremiumYearOne" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtDiscountPremiumYearTwo" abstract="false" name="AmortizationOfDebtDiscountPremiumYearTwo" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtDiscountPremiumYearThree" abstract="false" name="AmortizationOfDebtDiscountPremiumYearThree" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtDiscountPremiumYearFour" abstract="false" name="AmortizationOfDebtDiscountPremiumYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtDiscountPremiumAfterYearFour" abstract="false" name="AmortizationOfDebtDiscountPremiumAfterYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtIssuanceCostsYearTwo" abstract="false" name="AmortizationOfDebtIssuanceCostsYearTwo" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtIssuanceCostsYearThree" abstract="false" name="AmortizationOfDebtIssuanceCostsYearThree" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtIssuanceCostsYearFour" abstract="false" name="AmortizationOfDebtIssuanceCostsYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_AmortizationOfDebtIssuanceCostsAfterYearFour" abstract="false" name="AmortizationOfDebtIssuanceCostsAfterYearFour" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="mgni_KatieEvansMember" abstract="true" name="KatieEvansMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_DavidPearsonMember" abstract="true" name="DavidPearsonMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_AdamSorocaMember" abstract="true" name="AdamSorocaMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_JamesRossmanMember" abstract="true" name="JamesRossmanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_MichaelBarrettMember" abstract="true" name="MichaelBarrettMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_DavidDayMember" abstract="true" name="DavidDayMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="mgni_AaronSaltzMember" abstract="true" name="AaronSaltzMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
</xs:schema>
