In the EU, reverse engineering is allowed by law if the reason for doing so is interoperability by the one who owns a license to the product in question.

"The authorisation of the rightholder shall not be required where reproduction of the code and translation of its form within the meaning of points (a) and (b) of Article 4(1) are indispensable to obtain the information necessary to achieve the interoperability of an independently created computer program with other programs, provided that the following conditions are met:

(a) those acts are performed by the licensee or by another person having a right to use a copy of a program, or on their behalf by a person authorised to do so;

(b) the information necessary to achieve interoperability has not previously been readily available to the persons referred to in point (a); and

(c) those acts are confined to the parts of the original program which are necessary in order to achieve interoperability."

More information: https://www.vidstromlabs.com/blog/the-legal-boundaries-of-re...