Because this novel is studied in Indonesian literature courses at universities like UI or UGM, professors sometimes upload annotated PDFs (updated with discussion questions). Search for the title + "sastra Indonesia" to find these academic UPD files. These are generally safe and high-quality.
If you are looking to download the text, try the following search terms in academic databases or Indonesian literature repositories: raden mandasia si pencuri daging sapi pdf upd
Subject: Book Report on "Raden Mandasia Si Pencuri Daging Sapi" Because this novel is studied in Indonesian literature
Title: Raden Mandasia Si Pencuri Daging Sapi Author: Yustinus Trisno Wibowo Publisher: Gramedia Pustaka Utama Year of Publication: 2015 Subject: Book Report on "Raden Mandasia Si Pencuri
While the author and publisher deserve compensation for their work (buy the book if you can!), here is a pragmatic guide for academic or archival access regarding the "UPD" version.