In software development, psychological safety has emerged as a critical factor influencing team performance, collaboration, learning, and software quality. Although its relevance is widely acknowledged, few studies have thoroughly examined how psychological safety manifests and operates in software development contexts. This research aims to provide a comprehensive overview of psychological safety in software development by synthesizing the published literature on the topic. To this end, we conducted a literature study complemented by backward and forward snowballing to identify the most relevant primary studies. In total, 40 studies were selected and analyzed according to five main research questions, enabling a broad understanding of the current state of the art. Therefore, the documents below constitute the supplementary material of this article, providing additional information that complements the primary research. This material includes methodological details, extracted data, analysis procedures, expanded results, and other relevant content that support transparency, understanding, and replication of the study.