fitTwoDipoles() is a plugin for EEGLAB developed by Makoto Miyakoshi and Caterina Piazza. It uses an huristic approach to determine whether fitting bilateral symmetric two dipoles is more appropriate than not. The difficulty in doing it is that fitting two dipoles necessarily reduces residual variance from fitting theoretical dipole projection (r.v.), so you can't simply use r.v. as a cost function, hence some reasonable heuristic is required. Fitting a single dipole for the case of two bilaratel dipole can generate significantly large r.v., so using this application can save good ICs that have bilateral scalp projections (i.e. functional connectivity across hemisphere decomposed by ICA). The reference paper for this algorithm is Piazza et al. (2016) https://link.springer.com/chapter/10.1007/978-3-319-32703-7_22. See also a related paper that argued physiological significance of bilateral dipoles for a single IC in infancts. Piazza et al. (2020) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7080990/