For a library automation ontology, open source integrated library software can be used as a specific type of source data. Unlike proprietary library software, the open source software enables to use not only the visible software interface but also the source code.
The paper is focused on Evergreen, widely used open source library software, and explores the use of its localization files, i.e. files containing expressions used in the software and their translation to other languages. By testing the proposed methods for analyzing localization files and by creating pilot ontology was confirmed that the localization files are feasible data for domain ontology building.