Person
ʿAbd Allāh ibn Muhammad ﷺ (al-Ṭāhir, al-Ṭayyib)
عبد الله بن محمد ﷺ (الطاهر، الطيب)
al-Ṭāhir (the Pure), al-Ṭayyib (the Good)
Lifespan unknown Banū Hāshim
Second son of the Prophet ﷺ by Khadīja. Born after the Prophet's mission began (some say before, some after). Died as an infant in Mecca. After his death the Quraysh enemies mocked the Prophet ﷺ as al-abtar ("the cut-off one, with no male descendants") — Sūrat al-Kawthar (Q 108) was revealed in response: "It is your enemy who is the cut-off one."
Significance
Second son of the Prophet ﷺ by Khadīja. Born after the Prophet's mission began (some say before, some after). Died as an infant in Mecca. After his death the Quraysh enemies mocked the Prophet ﷺ as al-abtar ("the cut-off one, with no male descendants") — Sūrat al-Kawthar (Q 108) was revealed in response: "It is your enemy who is the cut-off one."
Sources: Wikipedia and classical Islamic biographical literature compiled by automated researchers. Every page is being continuously refined — if something looks off, please check back in a few days.