Background: Open Source Software (OSS) started as an effort of communities of volunteers, but its practices have been adopted far beyond these initial scenarios. For instance, the strategic use of OSS in industry is constantly growing nowadays in different verticals, including energy, automotive, and health. For the public sector, however, the adoption has lagged behind even if benefits particularly salient in the public sector context such as improved interoperability, transparency, and digital sovereignty have been pointed out. When Public Sector Organisations (PSOs) seek to engage with OSS, this introduces challenges as they often lack the necessary technical capabilities, while also being bound and influenced by regulations and practices for public procurement. Aim: We aim to shed light on how public sector OSS projects, i.e., projects initiated, developed and governed by public sector organizations, are developed and structured. We conjecture, based on the challenges of PSOs, that the way development is organized in these type of projects to a large extent disalign with the commonly adopted bazaar model (popularized by Eric Raymond), which implies that development is carried out collaboratively in a larger community. Method: We plan to contrast public sector OSS projects with a set of earlier reported case studies of bazaar OSS projects, including Mockus et al.'s reporting of the Apache web server and Mozilla browser OSS projects, along with the replications performed on the FreeBSD, JBossAS, JOnAS, and Apache Geronimo OSS projects. To enable comparable results, we will replicate the methodology used by Mockus et al. on a purposefully sampled subset of public sector OSS projects. The subset will be identified and characterized quantitatively by mining relevant software repositories, and qualitatively investigated through interviews with individuals from involved organizations.