A few years ago, Karla Monterroso was at an airport when she noticed a glitch in a computer monitor that would normally display flight information. Instead, the screen showed the text “Master/Slave,” repeated at least 10 times from top to bottom.

“I remember freaking out about it and going to [people working in] the terminal and letting them know that I thought that’s really inappropriate,” says Monterroso, CEO of Code 2040, a nonprofit dedicated to racial equality and inclusion in tech. “And they’re like, ‘No, that’s just the technology. That’s what the technology says.’”

The words “master” and “slave” have been widely used for decades in computing and other technical contexts, as a reference to situations where one process or entity controls another. Sometimes the metaphor is less precise: a “master” may simply lead, serve as a primary resource, or be considered first. Since 1976, the US has issued more than 67,000 patents using the terms, from an antenna system to a data encoding method to a “vehicle ramp assembly.”

Now, the Black Lives Matter movement is prompting renewed scrutiny of diversity and equity in tech—including its vocabulary.

Microsoft’s GitHub, a popular software development platform with 50 million users, will replace the word “master” as the default branch name for new repositories, a spokesperson says. GitHub is also making it easy for users to choose their own default branch name when creating a new repository, and releasing guidance to rename existing ones, the spokesperson says. There’s never been a complementary use of “slave” in GitHub’s repository architecture.

There are also discussions about changing the use of “master” within Git, the open-source project that’s the foundation of GitHub, says Christian Couder, a Paris-based member of the Git Project Leadership Committee. A Git repository stores the revision history for a set of files, such as source code for a software project. The default name for the main thread of that history has been “master.” In an email, the committee said it recently modified the code so users could set their own preferred default branch name.

As more organizations reexamine their language, coders are engaging in intense debates about the extent to which these words matter. If there is no “slave,” does “master” need to go? Are movements to change such words meaningful when so much else needs to be done to increase diversity, equity, and inclusion in the tech world?

Dwayne Slater, a developer in San Jose, is one of more than 3,000 people who signed a petition opposing GitHub dropping the word “master.” The petition calls such moves “distractions, not solutions,” and says it “creates confusion and unnecessary work for developers.” Slater, who is Black, wrote in the comments, “To see GitHub use the color of my skin to make meaningless change is a slap in the face. There are more useful causes to bring to attention, words are not the issue, police brutality in the United States is the issue.”

In an interview, Slater says he supports replacing the word “slave” where it’s still used. But on GitHub, Slater is fine with “master” because he thought of it in the sense of a “master copy” or “mastering a craft” during more than six years of using Git.

Stephen Stafford, a developer in San Diego, says reading the news about GitHub changing the term “master” was “an uncomfortable experience” for him, since he didn’t view it as a problem. Stafford, who is also Black, likened the move to the “performative activism” of Blackout Tuesday, in which people posted black squares on social media without necessarily doing anything else for the Black Lives Matter cause.