alt Hacker NewsLow count suggests that the project has an intentionally built core and doesn't undergo churn or feature creep. It's also a good sign that commits per week have decreased substantially over time.
Contributions being mostly from a single developer lends further credence to that idea, because it implies everything is fueled by one person's relatively opinionated vision and taste.
This conclusion is deeply divorced from reality.
A single(-ish) author is the strongest smell for a library. I've been burned countless times by a project's "BDFL" moving on to something else. Sometimes a new maintainer will take over, but it's rare.
Low commit count also suggests unresponsiveness to issues that are filed, especially for a TypeScript or JavaScript project.
This thread single-handedly convinced me not to start a Solid project.