Bailey diagrams of RRLs in GGCs associated with the in situ population (top left), RRLs in GGCs associated with the accreted population (bottom left), field RRLs associated with the in situ population (top right), and field RRLs associated with the accreted population (bottom right). Sources are colour-coded according to their metallicity. The red curve separating the two types of Oosterhoff dichotomies is described by the following polynomial: y = −8.70 ⋅ 10⁵ x⁷ − 1.63 ⋅ 10⁶ x⁶ − 1.28 ⋅ 10⁶ x⁵ − 5.44 ⋅ 10⁵ x⁴ − 1.35 ⋅ 10⁵ x³ − 1.95 ⋅ 10⁴ x² − 1.54 ⋅ 10³ x − 52.14.