Contributing to a growing body of research on broadening participation in computing for historically underrepresented racial communities (e.g., Black and Latinx), this qualitative study describes the knowledge (content and sources) six antiracist Computer Science (CS) teachers have about examples (and counterexamples) of modern techno-racism, a phenomenon in which "the racism experienced by people of color is encoded in the technical systems used in our everyday lives" (Nkonde, 2021). This study also shares teachers' descriptions about related pedagogical actions and their stories of becoming an antiracist CS educator. Findings demonstrate that no single technology or context is represented across all six teachers' sets of examples of techno-racism, but examples pertaining to AI, facial recognition, criminal justice, and social media were most frequently mentioned. Additionally, the blockchain was described by two teachers as a potential counterexample of techno-racism, and four teachers cited educator communities as a key source of learning. This study can inform the design of antiracist, equity-centered initiatives seeking to respond to the growing national need of K-12 CS educators. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://bibliotheek.ehb.be:2222/en-US/products/dissertations/individuals.shtml.]