What is localhost:8000 as used in Codecademy (for AngularJS and Ruby

ruby 8000The default timestamp rate is 8000 Hz, but other rates may be defined. RTP & Volatility. SIP-ALG-Detector is an utility to detect routers with SIP ALG enabled. Extra 10%INFORMASI RUBY8000 ; MINIMAL DEPOSIT, 10 RIBU RUPIAH ; MINIMAL WITHDRAW, 50 RIBU RUPIAH ; BANK TRANSAKSI, BCA, BNI, BRI, MANDIRI