Quick answer
HR-FR-LSH stands for Heat-Resistant, Flame-Retardant, Low Smoke & Halogen — and the 'HR' is the key here. Ordinary PVC house wire is rated for roughly 70 °C continuous; an HR-FR-LSH wire tolerates noticeably higher continuous operating temperatures (around 105 °C), and withstands the brief, intense heat of a short circuit far better.
That heat headroom matters for today's homes, where air-conditioners, geysers and dense circuits run hot. It also links to capacity: a higher temperature rating lets the same conductor carry more current safely — see ampacity.
APAR Anushakti HR-FR-LSH achieves this with e-beam cross-linked insulation; the premium Fire Protekt range goes higher still. Confirm exact ratings on the product datasheet.