Well, we have the actual text of the bill so we actually know quite a bit and it's not really just speculation.
Text for S.3548 - 116th Congress (2019-2020): CARES Act
www.congress.gov
Here's the relevant section:
'SEC. 6428. 2020 RECOVERY REBATES FOR INDIVIDUALS.
“(a) In General.—In the case of an eligible individual, there shall be allowed as a credit against the tax imposed by subtitle A for the first taxable year beginning in 2020 an amount equal to the lesser of—
“(1) net income tax liability, or
“(2) $1,200 ($2,400 in the case of a joint return).
“(b) Special Rules.—
“(1) IN GENERAL.—In the case of a taxpayer described in paragraph (2)—
“(A) the amount determined under subsection (a) shall not be less than $600 ($1,200 in the case of a joint return), and
“(B) the amount determined under subsection (a) (after the application of subparagraph (A)) shall be increased by the product of $500 multiplied by the number of qualifying children (within the meaning of section 24(c)) of the taxpayer.
“(2) TAXPAYER DESCRIBED.—A taxpayer is described in this paragraph if the taxpayer—
“(A) has qualifying income of at least $2,500, or
“(B) has—
“(i) net income tax liability which is greater than zero, and
“(ii) gross income which is greater than the basic standard deduction
“(c) Treatment Of Credit.—The credit allowed by subsection (a) shall be treated as allowed by subpart C of part IV of subchapter A of chapter 1.
“(d) Limitation Based On Adjusted Gross Income.—The amount of the credit allowed by subsection (a) (determined without regard to this subsection and subsection (f)) shall be reduced (but not below zero) by 5 percent of so much of the taxpayer’s adjusted gross income as exceeds $75,000 ($150,000 in the case of a joint return).