The 'Ɛ' and lower-case'ɛ' are new characters and make the long 'E' sound /ee/.
In the current alphabet, the letter 'E' or 'e' represent both the short /eh/ & long /ee/ speech sounds. 7M-English assigns new characters to separate the two vowels. The upper-case 'Ɛ' & lower-case 'ε' represent the long /ee/ sound, and the upper-case 'ꟻ' & lower-case 'e' represent the short /eh/ sound.