Round-trip format conversion
The term round-trip is used in document conversion particularly involving markup languages such as XML and SGML. Round-tripping consists of converting a document in format A (docA) to one in format B (docB) and then back again to format A (docA′). If docA and docA′ are identical then there has been no information loss and the round-trip has been successful.
Source: Wikipedia — Round-trip format conversion (CC BY-SA 4.0)