The word "Regular" is appeared in namerecord of all upstream ttf files. However only ipaexg.ttf(002.01) has the word "Regulare", it might be a typo.
$ ttx -t name ipaexg.ttf $ grep -C1 'Regulare' ipaexg.ttx ipaexg.ttx- <namerecord nameID="2" platformID="1" platEncID="0" langID="0x0"> ipaexg.ttx: Regulare ipaexg.ttx- </namerecord>
The word "Regular" is appeared in namerecord of all upstream ttf files. However only ipaexg.ttf(002.01) has the word "Regulare", it might be a typo.
$ ttx -t name ipaexg.ttf
$ grep -C1 'Regulare' ipaexg.ttx
ipaexg.ttx- <namerecord nameID="2" platformID="1" platEncID="0" langID="0x0">
ipaexg.ttx: Regulare
ipaexg.ttx- </namerecord>