Julie Ann Horvath, an influential developer known for helping make GitHub a more attractive place for women programmers to work, announced Friday night via Twitter that she had quit her job because of alleged harassment by GitHub “leadership”:

Horvath wasn’t very specific about her reasons for leaving GitHub. In hercommentsonTwitter, Horvath implied that she quit her job because of “aggressive behavior” that was disguised as “professional feedback.” She wrote that she faced unspecified “harassment” from GitHub “leadership” (a word she set in quotation marks) for two years, adding that “[w]hat I endured as an employee of GitHub was unacceptable and went unnoticed by most.”

Shortly thereafter, she added: “Also a reminder that what looks good from the outside may be systematically fucked on the inside.” Horvath also wrote that she hopes GitHub will ask the people “responsible for abuse and harassment” to resign. In response to a question on Twitter, Horvath confirmed that her alleged harassment wasn’t sexual in nature.

Horvath delivered her broadside against GitHub shortly after she’d complained on Twitter about a post on the anonymous service Secret that, she said, attempted to “assassinate my character.” The post on Secret, submitted by someone who referred to himself or herself as “greenshirt” (presumably because the account on Secret uses a green shirt as an avatar), accused Horvath of specific types of unprofessional conduct without providing details.

It’s unclear whether Horvath intends to go into more detail regarding her accusations. As of publication, she had not responded to requests for comment by email. On Friday evening, Horvath tweeted, “I will be writing about my experiences soon.” By Saturday afternoon, though, she hedged a bit with this tweet: “I’m only interested in telling my story so that others can learn from it. It seems like my comments here may have been enough.”

We have reached out to GitHub for comment and will update this piece when and if we learn more.

Until Horvath left, it looked like GitHub was becoming a significantly progressive anomaly in the tech world. Last year, Horvath founded Passion Projects—GitHub’s first and only talk series—which invites notable women in technology to talk about their careers.

Since Passion Projects began, GitHub ditched a rug that some minority programmers found offensive. During the second half of 2013, a quarter of GitHub’s most recent 60 hires were women—and some directly because of Passion Projects, according to then CEO Tom Preston-Werner.

Horvath’s departure puts a huge dent in GitHub’s women-friendly reputation, but she said she won’t stop her efforts to make the tech community a better place for women to work. Horvath said she’ll continue to give Passion Projects talks “on the road.”

“I’m not quitting tech. I’m not gonna hide. This is my community. These are my people,” she tweeted.

Update: An earlier version of this article briefly, but incorrectly, failed to acknowledge the difference between code hosted in a GitHub repository and GitHub’s own code.