When searching for the core repertoire of Lebrun on IMSLP, the central repository is the collection, published posthumously around 1804 by Johann Anton André. Lebrun Oboe Concerto Imslp
The available files on IMSLP typically include: lebrun oboe concerto imslp
As of the last major update, IMSLP hosts several complete scores and parts for Lebrun’s oboe concertos, primarily: When searching for the core repertoire of Lebrun