After nearly 20 years, the beloved, long-running children’s series “Reading Rainbow” is back, this time on the KidZuko YouTube channel. The first of four episodes hosted by Mychal Threets, a librarian and literacy advocate, will be released Saturday at 10 a.m. Eastern. “I was raised on Reading Rainbow, LeVar Burton is my hero,” Threets wrote on Instagram. News of the digital-only series, with accompanying vertical videos, comes as the federal government has eliminated $1.1 billion allocated to public broadcasting. The original series ran on public television stations around the country and was used often in schools.