The IRS link talking about 401(k) plan limits says:

https://www.irs.gov/retirement-plans/plan-participant-employee/retirement-topics-401k-and-profit-sharing-plan-contribution-limits

“However, an employer’s deduction for contributions to a defined contribution plan (profit-sharing plan or money purchase pension plan) cannot be more than 25% of the compensation paid (or accrued) during the year to eligible employees participating in the plan “

Does this 25% limit for how much employers can deduct from their taxable income also include employee aftertax contributions (used in megabackdoor Roth)?