When the scope of the invention is not clear, the classification has to be based on what appears to be the invention in so far as this can be understood. It is then necessary to amend it if obscurities are removed by the search, as discussed in B‑V, 3, last paragraph.
Source: http://www.epo.org/law-practice/legal-texts/html/guidelines/e/b_v_3_2.htm
Date retrieved: 17 May 2021