The former Facebook employee who gathered documents that formed the foundation of The Wall Street Journal’s Facebook Files series said she acted to help prompt change at the social-media giant, not to stir anger toward it.

Frances Haugen, a former product manager hired to help protect against election interference on Facebook, said she had grown frustrated by what she saw as the company’s lack of openness about its platforms’ potential for harm and unwillingness to address its flaws. She is scheduled to testify before Congress on Tuesday, 5 October. She has also sought federal whistleblower protection with the Securities and Exchange Commission.