System Information
Operating system: Linux-4.19.0-5-amd64-x86_64-with-debian-10.0 64 Bits
Graphics card: GeForce GTX 950/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 418.74

Blender Version
Broken: version: 2.80 (sub 74), branch: master, commit date: 2019-07-11 13:50, hash: rB06312c6d2db8
Worked: (optional)

Short description of error
Missing shortcut: shift+up/down arrow for interval frame offset in timeleine.

Exact steps for others to reproduce the error

in 2.7 shortcut: shift+up/down arrow for interval frame offset was prebuilt. Pressing shift+up/down arrow in timeline will jump +10 or -10 delta frames.

In 2.8 the shortcut is absent.

It is particularly important for GP 2d animation, Rotoscoping and Compositing.