SingleFile CLI 2.18.3

CLI fixes and improvements

• Update single-file-core to 1.6.31: the link added next to a blocked video stays on the video instead of landing at the top of the page when the video sits directly in <main> or <body>, and the infobar host turns off the ::before and ::after pseudo-elements a page stylesheet could draw on it.

Co-authored by Claude (Claude Code)