EEGLAB supports reading most MEG data formats through the File-IO module. Therefore all the major manufacturers may be imported (CTF, Neuromag, Neuroimaging 4-D, BTi). There is also the native ctfimport EEGLAB plugin to import CTF data.
MEG data may be processed as EEG data, although there is added complexity for some data formats. For example, EEGLAB does not differentiate between gradiometers and magnetometers for Neuromag data. For plotting purposes, you have to tweak the topoplot function to plot either one or the other.
Also, EEGLAB does not support MEG gradient correction, so you need to do that outside of EEGLAB before processing the MEG data in EEGLAB.
For MEG source localization, you can use a custom model in DIPFIT within EEGLAB (there is a specific entry for MEG custom leadfield matrix as explained here). EEGLAB is still a solution of choice if you are using Independent Component Analysis to extract brain sources from MEG data.
However, EEGLAB is not primarily designed to process MEG data and perform MEG source localization. For advanced MEG source processing that does not involve ICA, a large number of MEG users directly use MEG specialized software. For MEG source localization, some of the most popular tools include Fieldtrip, Brainstorm, MEG-tools, MEGSIM, NUTMEG, OpenMEG, MNE suite, or Curry. Some of the links on the popular NITRC platform are listed shown