To reproduce:
1. Open attached project 'LighweightCameraColorTexture.zip"
2. Switch the platform, tick "Development build" and "Autoconnect Profiler"
3. Build to a device
4. When project is built, go to the Profiler window in editor and start profiling the connected device
5. In Profiler window, go to Memory tab > Detailed > Take Sample
6. Check the sample tab > Not Saved > RenderTexture

Result: _CameraColorTexture takes 0.9 Gb of memory on an empty scene

Reproduced in: 2019.1.4f1, 2019.2.0b4, 2019.3.0a4
Not reproduced in: 2018.4.1f1

Note1: Reproduces on both Android (0.9 Gb) and iOS (~0.76 Gb). Reproduced on Vulkan, GLES3, with both variations of colors spaces. Also, resetting Project settings
to defaults still reproduces the issue, however does not reproduce on an empty project.
Note2: key elements for reproduction: originally provided project (no repro on similarly set up new project), LW set as SRP and a Camera in Scene
Note3: no package manager in 2017.4 LTS, therefore not tested, also 2019.1 could not be bisected as there's lots of package errors that are not fixed on package reset

Tested on devices:
VLNQA00272, Samsung Galaxy S10+ (SM-G975U), Android 9, CPU: Snapdragon 855 SM8150, GPU: Adreno (TM) 640
VLNQA00103, Samsung Galaxy Note8 (SM-N950F), Android 7.1.1, CPU: Exynos 9 Octa 8895, GPU: Mali-G71