Who were the בני ברית מערביים mentioned in the Trumas HaDeshen, and what was their agenda?

Question

The Trumas HaDeshen #88 in chelek 2, seen here discussed going to live in Eretz Yisroel in his times.

In his discussion he mentions

בני ברית מערביים נחשבים לרשעים גמורים מוסרים מפורסמים והם טורדים ומבלבלים האשכנזים שהם שומרי תורה

Who are these בני ברית מערביים and what were they doing? I'm assuming he means middle eastern Jews so I wonder if they were still practicing Judaism or perhaps they had converted to Islam. He does call them Bnei Bris, but at the same time he implies that the Ashkenzi (immigrants?) were the ones keeping the Torah. Why were these other people so intent on ruining it for the Ashkenazim?

Later on he mentions רשעת הישמעלים so these people were not Muslim, not that it's likely he would call a Muslim Bnei Bris.

A quick reference point, the author of Trumas HaDeshen Rabbi Yisroel Isserlein died 26 years before the Ottoman conquest of the Holy land, so whatever political issues were going on were still under the rule of the Mamluks

Answer 1

According to Rabbi Yehudah Leib Maimon in Sefer Zikaron Leshlomo Meir Sali, this is a reference to some Sephardic Jews living in Eretz Yisrael who would inform on the Jews who came to live in Yisrael, especially the Ashkenazim. These "mosrim" were considered at times among the "z'kenim" of Yerushalayim; meaning they were considered to being men of stature, though clearly, they weren't really. It seems they gained this status by inducing fear. Thus, by the time of Rabbi Ovadyah of Bartenura, a number of decades after Rabbi Isserlein, Yerushalayim's Jewish community had become considerably smaller. According to Rabbi Maimon, based on what the Bartenura wrote, it seems they did this purely for monetary reasons.

Rabbi Yisrael Hess in Or Hamizrach, vol. 21, also notes that this term refers to Sephardic Jews.

Dr. Avraham David in Al Bamotei Hatzvi, on the other hand, thought this may be a reference to the "Edah Hamughrabit", i.e., Jews from North Africa, who got into an inter-edah fight with the Ashkenazim, and not necessarily "z'kenim"-leaders. Rabbi Eliyahu Zini in Eretz Chemdatenu also wrote that this refers to North-African Jews.