Tapachrna che lakshan means the signs or characteristics of Tapas (austerities) in Jainism. In Jain texts, Tapas is a core form of self-discipline and penance, external and internal, to burn karma and progress toward liberation. “Lakshan” here indicates the defining qualities or aspects associated with Tapas, and in many contexts it is listed as one of the ten Das Lakshan (the ten supreme virtues) especially in the Digambar tradition. So, the phrase points to the attributes that characterize true Tapas, such as self-control, endurance, and renunciation, as part of the Jain path. You can read more here and here