Convert xbm to heif
A browser can't do this one — here is what it can do.
Desktop app only
Nothing that runs in a tab can write heif from xbm. This pair is waiting on the desktop build, which hands the job to the real command-line tools.
Browse what does workAbout XBM
X BitMap
A black and white image format from the X Window System, stored as C source code so it can be compiled straight into a program. Use it for X11 cursors and icons; convert from it to see the image in a normal viewer.
About HEIF
High Efficiency Image File Format
An MPEG container standard (ISO/IEC 23008-12) from 2015 for single images and image sequences. It can hold HEVC, AV1 or other codecs, along with depth maps and bursts. Convert HEIF to JPG or PNG for apps and sites that cannot read it.