What is “a purchase agreement and registration rights agreement,” and what are the possible implications?

I'm new to DD, never really looked at a quarterly report before. This is the part I'm trying to understand:

“On May 11, 2022, Fast Radius entered into a purchase agreement and registration rights agreement with Lincoln Park Capital (“Lincoln Park”), a Chicago-based institutional investor, whereby, over a 24-month period, Fast Radius will have the right and the sole discretion to sell to Lincoln Park up to $30 million worth of common stock. Any proceeds realized may be used at Fast Radius’ discretion and are available on an as-needed basis, subject to the terms and conditions of the agreements, market conditions and other factors, providing Fast Radius with additional liquidity.”

The current market cap of the stock is around $45M, so $30M seems like a huge chunk of that…