As of this writing and included in the link below the IRS does not specify as to what type of plan to repay the funds other than an Eligible Retirement Plan. see Q7
According to IRS you may repay all or part of the amount of a coronavirus-related distribution to an eligible retirement plan, provided that you complete the repayment within three years after the date that the distribution was received. If you repay a coronavirus-related distribution, the distribution will be treated as though it were repaid in a direct trustee-to-trustee transfer so that you do not owe federal income tax on the distribution.
You can pay the withdrawal back in payments or one lump sum. If you do not pay it back you will pay tax on it.
If, for example, you receive a coronavirus-related distribution in 2020, you choose to include the distribution amount in income over a 3-year period (2020, 2021, and 2022), and you choose to repay the full amount to an eligible retirement plan in 2022, you may file amended federal income tax returns for 2020 and 2021 to claim a refund of the tax attributable to the amount of the distribution that you included in income for those years, and you will not be required to include any amount in income in 2022.
Coronavirus-related relief for retirement plans and IRAs ...
