Read the leaked report. According to this article by Sarah Kliff, the report, produced by the health research firm Avalere Health and the consulting firm McKinsey and Company
includes graphs on what the Republican plan to overhaul Obamacare’s tax credits, generally making them less generous, would do. [The report's projections] are based on the recent 19-page proposal that Republican leadership released about their plan to repeal and replace Obamacare. In particular, [the report] look[s] at the effect of switching from income-based tax credits (which give poor people more help) to age-based tax credits, where everyone would get the same amount.