Az Zutt (الزط) - Jaat or Jatt, people of sub continent.
Az Zutt is an arabic word which means Jaat or Jatt this tribe belongs to subcontinent and also the people of this tribe resided in Arab from a very long time. These people lived in Sindh, Punjab and according to some historians they also lived in Balochistan.
It is mentioned in Lisaan al Arab
الزط جيل اسود من السند بالهندية وهوجيل من اهل الهند وهم جنس من السودان والهنود
The Zutt people are from the Sindh who are dark in skin, and these people belong to India, they are dark in complexion and from the Indian genes.
[Lisaan al Arab 7/308]
It is mentioned in an authentic hadith narrated by Ibn Abbas رضیﷲ عنه that Saydna Mohammad صلی اللہ علیہ وسلم described the physical appearance of Moosa عليه السلام (Moses) same as the people of Az Zutt (Jatt/Jaat)
Saydna Ibn Abbas رضیﷲ عنه reported that Rasoolallah صلی اللہ علیہ وسلم said:
وَأَمَّا مُوسَى فَآدَمُ جَسِيمٌ سَبْطٌ كَأَنَّهُ مِنْ رِجَالِ الزُّطّ.
Moses was of brown complexion, straight hair and tall stature as if he was from the people of Az-Zutt (Jaat/Jatt).
[Sahih al Bukhari 3438]
It is mentioned in the historical records that when a group of muslims from Banu Harith bin Ka'ab sent from Najran and when they came to Rasoolallah صلی اللہ علیہ وسلم so after seeing them Mohammad صلی اللہ علیہ وسلم said:
من هولاء القوم كانهم رجال الهند
Who are these people who seems to be Indian.
[Tarikh Tabri 3/156]
The Jatt who informed Aisha رضیﷲ عنہا that she is bewitched.
Amra reported that 'A'isha رضیﷲ عنه had made one of her slavegirls a mudabbar (one who would be set free after her death). Then 'A'isha رضیﷲ عنہا became ill and her nephews consulted a gypsy doctor from Jatt (طَبِيبًا مِنَ الزُّطِّ).
He said, "You are asking me for information about a bewitched woman. A slavegirl of hers has bewitched her." 'A'isha رضیﷲ عنہاwas told and asked the girl, "Have you put a spell on me?" "Yes," she replied. "Why?' she asked. "Because you will never free me," she answered. Then 'A'isha رضیﷲ عنہا said, "Sell her to the worst masters among the Arabs."
[Al-Adab Al-Mufrad 162 Sahih by Albani رحمہ اللہ]
As per the historian Muhammad Ishaq Bhatti that gypsy doctor was from the caste "Jutt" الزُّطِّ in Arabic as mentioned in the hadith, the famous cast of subcontinent, and he accepted Islam.