Can top-level domains contain a number at the end? Idk nothing about DNS rules etc but when I try to use PHP\'s filter_var() function with FILTER_VALIDATE_EMAIL for te
Actually there are quite a few TLDs currently in use that contain numbers:
XN--1QQW23A XN--3BST00M XN--3DS443G XN--3E0B707E XN--45BRJ9C XN--4GBRIM XN--55QW42G XN--55QX5D XN--6FRZ82G XN--6QQ986B3XL XN--80ADXHKS XN--80AO21A XN--80ASEHDB XN--80ASWG XN--90A3AC XN--C1AVG XN--CG4BKI XN--CLCHC0EA0B2G2A9GCD XN--CZR694B XN--CZRU2D XN--D1ACJ3B XN--FIQ228C5HS XN--FIQ64B XN--FIQS8S XN--FIQZ9S XN--FPCRJ9C3D XN--FZC2C9E2C XN--GECRJ9C XN--H2BRJ9C XN--I1B6B1A6A2E XN--IO0A7I XN--J1AMH XN--J6W193G XN--KPRW13D XN--KPRY57D XN--KPUT3I XN--L1ACC XN--LGBBAT1AD8J XN--MGB9AWBF XN--MGBA3A4F16A XN--MGBAAM7A8H XN--MGBAB2BD XN--MGBAYH7GPA XN--MGBBH1A71E XN--MGBC0A9AZCG XN--MGBERP4A5D4AR XN--MGBX4CD0AB XN--NGBC5AZD XN--NQV7F XN--NQV7FS00EMA XN--O3CW4H XN--OGBPF8FL XN--P1AI XN--PGBS0DH XN--Q9JYB4C XN--RHQV96G XN--S9BRJ9C XN--SES554G XN--UNUP4Y XN--VHQUV XN--WGBH1C XN--WGBL6A XN--XHQ521B XN--XKC2AL3HYE2A XN--XKC2DL3A5EE0H XN--YFRO4I67O XN--YGBI2AMMX XN--ZFR164B
You can see an up to date list here data.iana.org/TLD/tlds-alpha-by-domain.txt or a list with descriptions here swcs.com.au/tld.htm