Microsoft-owned GitHub recently renewed a contract with Immigration and Customs Enforcement, the agency responsible for carrying out the Trump administration's controversial immigration policies.A group of open-source developers sent an open letter asking GitHub to cancel its contract with ICE and set higher ethical standards for its business dealings.GitHub has yet to respond to a request for more information, but company CEO Nat Friedman has defended the contract, saying it would be wrong for it to demand to know what customers do with its tools.The letter is the latest in a series of protests seeking to pressure GitHub into cancelling the agreement.It's also the latest example of a surge of activism from developers who want more control over how the technology they create is used.Click here to read more BI Prime storiesA group of open-source developers sent an open letter to GitHub on Wednesday asking the Microsoft-owned code-sharing service to cancel its contract with Immigration and Customs Enforcement and set new ethical standards.The contract puts GitHub at odds with the values of the open-source development community, its primary user base, the 55 signed developers wrote in the letter. They called on the company to set higher ethical standards for its business dealings and share those standards publicly."At the core of the open source ethos is the idea of liberty," the developers wrote in the letter. "Open source is about inverting power structures and creating access and opportunities for everyone. We, the undersigned, cannot see how to reconcile our ethics with GitHub's continued support of ICE."GitHub did not immediately respond to a request for comment on the letter. But company CEO Nat Friedman has previously defended the contract, saying it would be wrong for GitHub to demand to know what its customers do with its tools.The company renewed its ICE contract in September. The deal provide an enterprise server license to the agency, which has been at the center of the Trump administration's controversial immigration policies, including the separation of families at the US border with Mexico.Backlash from employeesThe developer letter is the latest in a series of protests seeking to pressure GitHub into cancelling the contract. A small group of employees have resigned over the agreement, including one as recently as Tuesday, according to post from a Twitter user who identified himself as a resigning GitHub employee. Last month, some 150 GitHub employees signed a letter urging the company to tear up the contract."GitHub has held a 'seat at the table' for over two years, as these illegal and dehumanizing policies have escalated, with little to show for it," the employees wrote. "Continuing to hold this contract does not improve our bargaining power with ICE. All it does is make us complicit in their widespread human rights abuses."For his part, in the face of that pressure, Friedman has stood by the contract."Just as Microsoft for more than three decades has licensed Microsoft Word without demanding to know what customers use it to write, we believe it would be wrong for GitHub to demand that software developers tell us what they are using our tools to do," Friedman wrote in an October email to employees.In the email, Friedman pledged to spend $500,000 on immigration-related nonprofits and advocate for political reform.The bigger pictureThe backlash over contracts with ICE is part of a larger surge of activism from developers who want more control over how the technology they create is used, as Business Insider's Rosalie Chan recently reported.GitHub owner Microsoft's own agreement with ICE, for example, was also controversial among its employees. Last summer, more than 100 Microsoft workers signed an open letter urging the company to terminate its $19.4 million ICE contract and stop working with the agency altogether. In response, Microsoft CEO Satya Nadella downplayed the company's relationship with ICE.Microsoft employees have also protested the company's $10 billion cloud contract with the Pentagon and another contract with the US military to develop augmented-reality headsets for soldiers. One group of employees charged that the latter agreement "crossed the line into weapons development."Got a tip'Contact this reporter via email firstname.lastname@example.org, message her on Twitter@ashannstew or send her a secure message through Signal at 425-344-8242.SEE ALSO:GitHub is facing an employee backlash as its CEO defends a $200,000 contract with ICE: 'All it does is make us complicit'Join the conversation about this storyNOW WATCH: How to find water when you're stuck in the desert Click here to read full news..